Barcode reader

ABSTRACT

A barcode reader may include an image sensor array, an optic system, an image buffer, and a plurality of pre-processing circuits implemented in hardware. The optic system may be configured to focus an image of a barcode onto the image sensor array. The plurality of pre-processing circuits may collectively implement a plurality of different image processing functions. Each pre-processing circuit may be configured to receive as input an image frame from the image sensor array or an image data record from the image buffer. The image data record may be derived from the image frame. Each pre-processing circuit may also be configured to perform an image processing function with respect to the image frame or the image data record, thereby generating a new image data record. A decoder may use at least one image data record to decode the barcode.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.15/676,397 (the '397 Application), titled “BARCODE READER CONFIGURED FORIMAGE PRE-PROCESSING,” filed Aug. 14, 2017, with inventors Mark Ashby,Ming Lei, and Ryan Hoobler. The '397 Application is a continuation ofU.S. patent application Ser. No. 14/717,193, issued as U.S. Pat. No.9,734,374 (the '374 Patent) on Nov. 3, 2016, titled “BARCODE READERCONFIGURED FOR FAST IMAGE READ-OUT,” filed May 20, 2015, with inventorsMark Ashby, Ming Lei, and Ryan Hoobler. The '374 Patent claims thebenefit of provisional U.S. Patent Application No. 62/154,066, titled“BARCODE READER,” filed Apr. 28, 2015, with inventors Ming Lei, MarkAshby, and Ryan Hoobler. The aforementioned applications areincorporated herein by reference as if fully set forth.

TECHNICAL FIELD

The present disclosure relates generally to a barcode reader. Morespecifically, the present disclosure relates to a barcode reader thatincludes multiple illumination systems and multiple sets of imagingoptics.

BACKGROUND

A barcode is an optical machine-readable representation of information.Devices for identifying or extracting information from barcodes aregenerally referred to as barcode readers (or barcode scanners). Animage-based barcode reader includes a camera for capturing an image of abarcode to be read. The camera includes a focusing lens that focuseslight reflected from a target area onto a photo sensor array. Once animage of a barcode has been captured by the camera, a decoder processesthe image and extracts the information contained in the barcode.

SUMMARY

In accordance with one aspect of the present disclosure, a barcodereader that includes an image sensor array, an optic system, an imagebuffer, a plurality of pre-processing circuits, a processor, memory inelectronic communication with the processor, and a decoder is disclosed.The optic system may be configured to focus an image of a barcode ontothe image sensor array. The plurality of pre-processing circuits may beimplemented in hardware, and may collectively implement a plurality ofdifferent image processing functions. Each pre-processing circuit may beconfigured to receive as input an image frame from the image sensorarray or an image data record from the image buffer. The image datarecord may be derived from the image frame. Each pre-processing circuitmay also be configured to perform an image processing function withrespect to the image frame or the image data record, thereby generatinga new image data record. The decoder may be stored in the memory and maybe executable by the processor to use at least one image data record todecode the barcode.

The plurality of different image processing functions may include atleast two of cropping, binning, subsampling, rotating, binarizing, andconvolving.

The plurality of pre-processing circuits may include a firstpre-processing circuit that is configured to apply a first convolutionkernel to the image frame or at least one image data record that isderived from the image frame. The plurality of pre-processing circuitsmay also include a second pre-processing circuit that is configured toapply a second convolution kernel, distinct from the first convolutionkernel, to at least one image data record generated by the firstpre-processing circuit.

The barcode reader may further include an image sensor system package,an image capture control and decode system, and an interface. The imagesensor system package may include a photo sensor array and imageread-out circuitry. The image capture control and decode system mayinclude the processor, the memory, and the decoder stored in the memory.The interface may couple the image sensor system package to the imagecapture control and decode system. The plurality of pre-processingcircuits may include a first set of pre-processing circuits within theimage sensor system package and a second set of pre-processing circuitswithin the image capture control and decode system.

The image sensor system package may further include control circuitry.The control circuitry may be configured to receive image captureparameter values from the image capture control and decode system viathe interface. The image capture parameter values may define one or moreimage frames to be captured and indicate at least one pre-processingfunction to apply to the one or more image frames. The control circuitrymay also be configured to control the first set of pre-processingcircuits such that each captured image frame is input to one or morepre-processing circuits within the first set of pre-processing circuitsin accordance with the image capture parameter values.

In accordance with another aspect of the present disclosure, a barcodereader may include an image sensor system package, an optic system, animage capture control and decode system, and an interface. The imagesensor system package may include a photo sensor array, image read-outcircuitry, and a first set of pre-processing circuits implemented inhardware. The optic system may focus illumination from a field of viewof the barcode reader onto the photo sensor array. The image capturecontrol and decode system may include a second set of pre-processingcircuits implemented in hardware, a processor, memory, and a decoderstored in the memory. The interface may couple the image sensor systempackage to the image capture control and decode system. The first set ofpre-processing circuits and the second set of pre-processing circuitsmay be configured to perform a plurality of different image processingfunctions to generate a plurality of different image data records.

Each image processing function of the plurality of different imageprocessing functions may be performed with respect to an image frame oran image data record that is derived from the image frame. Each imagedata record of the plurality of different image data records may bederived from the image frame.

The plurality of different image processing functions may include atleast two of cropping, binning, subsampling, rotating, binarizing, andconvolving.

The first set of pre-processing circuits and the second set ofpre-processing circuits may include a first pre-processing circuit and asecond pre-processing circuit. The first pre-processing circuit may beconfigured to apply a first convolution kernel to an image frame or animage data record that is derived from the image frame. The secondpre-processing circuit may be configured to apply a second convolutionkernel, distinct from the first convolution kernel, to a new image datarecord generated by the first pre-processing circuit

The interface may include a control link and one or more data lines. Thecontrol link may enable the image capture control and decode system toselect which pre-processing circuits within the first set ofpre-processing circuits are to be applied to each captured frame. Thecontrol link may also enable the image capture control and decode systemto select one or more of the plurality of different image data recordsfor transfer to the image capture control and decode system. The one ormore data lines may provide for transfer of selected image data recordsfrom the image sensor system package to the image capture control anddecode system.

The image sensor system package may include a first image buffer. Eachpre-processing circuit within the first set of pre-processing circuitsmay be configured to receive an image frame captured by the photo sensorarray or an image data record from the first image buffer. The imagedata record may be derived from the image frame. Each pre-processingcircuit within the first set of pre-processing circuits may also beconfigured to perform an image processing function with respect to theimage frame or the image data record.

The image capture control and decode system may include a second imagebuffer. Each pre-processing circuit within the second set ofpre-processing circuits may be configured to receive an image datarecord from the image sensor system package via the interface or fromthe second image buffer. Each pre-processing circuit within the secondset of pre-processing circuits may also be configured to perform animage processing function with respect to the image data record.

The image sensor system package may further include control circuitrythat is configured to receive image capture parameter values from theimage capture control and decode system via the interface. The imagecapture parameter values may define one or more image frames to becaptured and indicate at least one pre-processing function to apply tothe one or more image frames. The control circuitry may also beconfigured to control the first set of pre-processing circuits such thateach captured image frame is input to one or more pre-processingcircuits within the first set of pre-processing circuits in accordancewith the image capture parameter values.

The control circuitry may be additionally configured to provide at leastsome image data records generated by the first set of pre-processingcircuits to the image capture control and decode system for additionalprocessing and decoding.

The image sensor system package may further include a first imagebuffer. The decoder may be configured to determine which image datarecords should be transferred from the first image buffer to the imagecapture control and decode system via the interface. The decoder mayalso be configured to determine which additional image processingoperations should be applied to transferred image data records by thesecond set of pre-processing circuits, thereby yielding additional imagedata records. The decoder may also be configured to select one of theadditional image data records to use for decoding a barcode.

The image capture control and decode system may further include an imageprocessing module stored in the memory. The image processing module maybe executable by the processor to perform additional image processingoperations.

In accordance with another aspect of the present disclosure, a methodfor reading a barcode is disclosed. The method may include capturing, bya photo sensor array, an image frame including the barcode. The methodmay also include performing a plurality of different image processingfunctions to generate a plurality of image data records that are derivedfrom the image frame. The plurality of different image processingfunctions may be performed by a plurality of pre-processing circuitsthat are coupled to the photo sensor array. The plurality ofpre-processing circuits may be implemented in hardware. The method mayalso include selecting at least one of the plurality of image datarecords for decoding the barcode.

Each image processing function of the plurality of different imageprocessing functions may be performed with respect to the image frame oran image data record that is derived from the image frame. The pluralityof different image processing functions may include at least two ofcropping, binning, subsampling, rotating, binarizing, and convolving.

Performing the plurality of different image processing functions mayinclude applying a first convolution kernel to the image frame or animage data record derived from the image frame. Performing the pluralityof different image processing functions may also include applying asecond convolution kernel, distinct from the first convolution kernel,to a new image data record generated by applying the first convolutionkernel to the image frame or the image data record derived from theimage frame.

The method may further include capturing, by the photo sensor array, aburst of multiple image frames. The method may also include providingpermutations of different image frames of the burst as input todifferent subsets of the plurality of pre-processing circuits.

A number of features are described herein with respect to embodiments ofthe invention. It will be appreciated that features described withrespect to a given embodiment also may be employed in connection withother embodiments.

The invention includes the features described herein, including thedescription, the annexed drawings, and, if appended, the claims, whichset forth in detail certain illustrative embodiments. These embodimentsare indicative, however, of but a few of the various ways in which theprinciples of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top-down view of a barcode reader in accordance with oneembodiment of the present disclosure.

FIGS. 2A-2E are front views of an optical substrate within the barcodereader shown in FIG. 1 in accordance with different embodiments of thepresent disclosure.

FIGS. 3A-3F illustrate cross-sectional views of the optical substrate,taken along the line A-A in FIGS. 2A-2C in accordance with differentembodiments of the present disclosure.

FIGS. 4A-4C are cross-sectional views of the optical substrate inaccordance with alternative embodiments.

FIG. 5 is a top-down view of a barcode reader in accordance with anotherembodiment of the present disclosure.

FIG. 6 is a top-down view of a barcode reader in accordance with anotherembodiment of the present disclosure.

FIG. 7 is a top-down view of a barcode reader in accordance with anotherembodiment of the present disclosure.

FIGS. 8A-8B are cross-sectional views of tertiary light sourcesilluminating the optical substrate in accordance with some embodimentsof the present disclosure.

FIG. 9A is a block diagram representative of a barcode reader includingan image capture control and decode system in combination with an imagesensor system package, an illumination system, and various input/output(I/O) peripheral systems in accordance with one embodiment of thepresent disclosure.

FIG. 9B shows image read-out circuitry and an operation of an imagereading out in accordance with one embodiment of the present disclosure.

FIG. 9C shows image read-out circuitry and an operation of an imagereading out in accordance with another embodiment of the presentdisclosure.

FIG. 9D shows an example of an interface between the control circuitryin the image sensor system package and the image capture control anddecode system.

FIG. 10 illustrates an example of a method for selecting an image datarecord in accordance with one embodiment.

FIG. 11 illustrates an example of a method for decoding an image datarecord in accordance with one embodiment.

FIGS. 12A-12D show examples of pre-processing in accordance with someembodiments of the present disclosure.

FIGS. 13A and 13B show examples of a frame of image data generated withdifferent settings in accordance with embodiments of the presentdisclosure.

FIG. 14 shows exemplary derivatives of a frame of image data produced bypermutations of pre-processing circuits and/or an image processingmodule.

DETAILED DESCRIPTION

FIG. 1 is a top-down view of an exemplary barcode reader 100 inaccordance with one embodiment of the present disclosure. The barcodereader 100 includes a housing 101, a photo sensor array 102 (i.e., animage sensor array), an optic system 104 for focusing an image of abarcode (not shown) within a field of view 106 onto the photo sensorarray 102, an image sensor system package 111, an image capture controland decode system 107, and an illumination system 103. The image sensorsystem package 111 captures an image of the barcode focused onto thephoto sensor array 102. The image capture control and decode system 107controls: i) the illumination system 103; ii) the image sensor systempackage 111; and iii) decoding of the captured image. A more detaileddiscussion of the image sensor system package 111 and the image capturecontrol and decode system 107 is included herein.

The field of view 106 imaged by the optic system 104 onto the photosensor array 102 is directed along an optical axis 114 perpendicular toa plane of the photo sensor array 102 and extends though the opticsystem 104. The optic system 104 may be located near a center of thephoto sensor array 102 (in both the vertical and horizontal dimensions)such that the optical axis 114 is centered on the photo sensor array102.

The optic system 104 may comprise a single lens or series of lensescapable of focusing: i) illumination reflected from objects within thefield of view 106 such as a barcode printed or otherwise marked on asubstrate; and ii) illumination emitted from objects within the field ofview 106 such as a barcode rendered on a back-lit display screen. Ineach case, the illumination is focused onto the photo sensor array 102.

The illumination system 103 is configured to illuminate the barcodewithin the field of view 106 during image capture. The illuminationsystem 103 may include multiple illuminating sub-systems such as adirect bright field illumination sub-system 108 (which may also bereferred to as a far field illumination sub-system), a diffuse brightfield illumination sub-system 105 (which may also be referred to as amid-range illumination sub-system), and a dark field illuminationsub-system 152 (which may also be referred to as a close-rangeillumination sub-system).

The direct bright field illumination sub-system (i.e., a far fieldillumination sub-system) 108 may comprise one or more light sources 108a-b, each of which may be a light-emitting diode (LED) light source. Inone embodiment, each of the one or more light sources 108 a-b may be ared LED with illumination of approximately 650 nm. Light from the one ormore light sources 108 a-b may emit direct illumination 112 into thefield of view 106 substantially parallel to the optical axis 114 butwith a slight convergence angle. For example, the one or more lightsources 108 a-b may emit direct illumination into the field of view 106at an angle from 0-30 degrees from the optical axis 114. As indicatedabove, the optical axis 114 is a line perpendicular to the photo sensorarray 102 and originating therefrom through the center of the opticsystem 104 (e.g., a focusing lens) and extending outward into the centerof the field of view 106.

Light emitted by the direct bright field illumination sub-system 108 maybe suited for reading a barcode with a diffuse surface such as a paperlabel and may be optimal for reading a barcode that is located in anarea of the field of view 106 that is relatively far away from thebarcode reader 100. Such an area may be referred to as a far zone 116 ofthe field of view 106. Stated alternatively, the direct illumination 112from the direct bright field illumination sub-system 108 may have asufficient intensity to adequately illuminate a barcode that is locatedwithin the far zone 116 for imaging by the optic system 104 onto thephoto sensor array 102. The far zone 116 may begin at a far zonestarting boundary 118 and end at a far zone ending boundary 119. In oneimplementation, the far zone starting boundary 118 may be located about75 mm away from the barcode reader 100.

The direct illumination 112 emitted by the direct bright fieldillumination sub-system 108 may not be sufficiently diffuse to provideoptimal illumination for reading a barcode that has a reflective surfaceor is positioned closer to the barcode reader 100 than to the far zone116. More specifically, the direct illumination 112 may create brightspots or hotspots when illuminating a barcode with a reflective(non-diffuse) surface or when illuminating a barcode placed closer tothe barcode reader 100 than to the far zone 116.

The diffuse bright field illumination sub-system (i.e., the mid-rangeillumination sub-system) 105 may emit diffuse light optimal for readinga barcode positioned within a close zone 158 and/or a center zone 126 ofthe field of view 106. The center zone 126 may begin at a center zonestarting boundary 128 and end at a center zone ending boundary 130. Thecenter zone starting boundary 128 is closer to the barcode reader 100than to a far zone starting boundary 118. For example, the center zonestarting boundary 128 may be located approximately 25 mm away from thebarcode reader 100. The center zone ending boundary 130 may be locatedwithin the far zone 116. Thus, the center zone 126 and the far zone 116may overlap.

The close zone 158 of the field of view 106 may begin at a close zonestarting boundary 160 and may end at a close zone ending boundary 162.The close zone starting boundary 160 may be closer to the barcode reader100 than to the center zone starting boundary 128. The close zonestarting boundary 160 may correspond to the face of the barcode reader100. The close zone ending boundary 162 may be within the center zone126. Thus, the close zone 158 and the center zone 126 may overlap.

The diffuse bright field illumination sub-system 105 may include atleast one light source 120 and an optical substrate 122 including one ormore extraction features. The optical substrate 122 has a front majorsurface 140 and a back major surface 138 arranged generallyperpendicular to the optical axis 114. Illumination is introduced fromthe at least one light source 120 between the front major surface 140and the back major surface 138 (shown in FIGS. 3A-3F and 4A-4C). Theillumination introduced by the at least one light source 120 istransferred by total internal reflection through the optical substrate122 between the front major surface 140 and the back major surface 138in a direction transverse to the optical axis 114. For example, in FIG.1, the light propagates through the optical substrate 122 in a directiongenerally perpendicular to the optical axis 114.

In an alternative embodiment depicted in the cross sectional views ofthe optical substrate 122 of FIGS. 3B and 3C, the at least one lightsource 120 introduces illumination into the optical substrate 122through the back major surface 138. In this example, the opticalsubstrate 122 has a chamfered edge 125 that reflects light in direction191 through a total internal reflection towards the optical axis 114.

As shown in FIGS. 1, 2A, 3A, and 3D to 3F, the at least one light source120 may be positioned adjacent an edge 186 of the optical substrate 122.In this configuration, as shown in FIG. 2A, light may exit the at leastone light source 120 through a single light-emitting surface (lightleaving the light-emitting surface is represented by arrows 190 a-d).

Alternatively, as shown in FIGS. 2B, 3B, and 3C, the at least one lightsource 120 may be positioned on the back major surface 138 in recesses121 a-f. In this configuration, light (i.e., light leaving thelight-emitting surface) may exit the at least one light source 120through a single light-emitting surface and be reflected from thechamfered edge 125 and directed towards the optical axis in direction191.

Alternatively, as shown in FIG. 2C, the at least one light source 120may be positioned within a recess 121 in the optical substrate 122. Inthis example, the at least one light source 120 may emit light frommultiple light-emitting surfaces and the light from all of thelight-emitting surfaces may enter the optical substrate 122.

Referring to FIG. 2D, the at least one light source 120 may be reducedto four (4) light sources, each of which is arranged on one exterioredge of the substrate 122 at a location that is not centered on theedge. For example, light source 120 a may be on a side edge lower thanthe center while light source 120 c may be on the opposing side higherthan the center. Light source 120 d may be on the top edge to the rightof center while light source 120 b may be on the bottom edge to the leftof center.

Referring to FIGS. 1 and 2A, the one or more light sources 120 maycomprise multiple LEDs. As will be understood by one of ordinary skillin the art, the one or more light sources 120 may comprise any suitablelight-emitting device. Further, the multiple light sources 120 may emitillumination with different characteristics. For example, a portion ofthe light sources 120 may be white LEDs while another portion may be redLEDs, or LEDs of another color.

As shown in FIG. 1, the optical substrate 122 may comprise asubstantially flat plate. For example, the optical substrate 122 maycomprise a clear and colorless acrylic substrate which may be made fromany other material suitable for transferring light by total internalreflection. The optical substrate 122 may be positioned within thebarcode reader 100 so that a front major surface 140 and a back majorsurface 138 of the optical substrate 122 are located in a plane that issubstantially perpendicular to the optical axis 114. In one embodiment,“substantially perpendicular” means within five degrees of perpendicularwhile in an alternative embodiment “substantially perpendicular” meanswithin 15 or 20 degrees of perpendicular.

The light emitted from the optical substrate 122 may have differentcharacteristics depending on the characteristics of the opticalsubstrate 122. For example, the optical substrate 122 may utilizerefraction, diffusion, prismatic effect, and/or total internalreflection to direct more diffuse illumination 124 into the field ofview 106. Depending on the properties of the optical substrate 122 andthe at least one light source 120, the illumination system may bereferred to as a diffuse bright field illumination sub-system. Thediffuse bright field illumination sub-system may also be called amid-field illumination system or a medium field illumination system.

In one embodiment, the light emitted from the optical substrate 122 maybe emitted substantially parallel to the optical axis 114. For example,light may be emitted within 10 degrees of parallel to the optical axis114. Illumination having a smaller angle spread around the optical axis114 may be referred to herein as diffuse bright field illumination 124.

Alternatively, referring to FIGS. 4A to 4C, the optical substrate 122may be shaped such that the shape of the front major surface 140 and/orthe back major surface 138 may be concave, convex, parabolic, or somecombination thereof. For example, as shown in FIG. 4A, the opticalsubstrate 122 has a generally concave-shaped front major surface 140 anda convex-shaped back major surface 138, while in FIG. 4B, the opticalsubstrate 122 has a generally convex-shaped front major surface 140 anda concave-shaped back major surface 138. The shape of at least one ofthe front major surface 140 and the back major surface 138 need not besymmetrical, but may be asymmetrical about a plane perpendicular to theoptical axis 114. In FIG. 4C, the front major surface 140 may includethree generally planar sections with the central section being generallyperpendicular to the optic axis 114 and two generally planar sectionsadjacent to, and on opposing sides of, the central section, being at anangle relative to the optic axis. In one embodiment the angle may be nogreater than 45 degrees. In this embodiment the back major surface 138may also include corresponding sections with the central section beinggenerally perpendicular to the optic axis 114 and two generally planarsections adjacent to, and on opposing sides of, the central section,being at an angle relative to the optic axis. In one embodiment, theangle of the two opposing sides of the back major surface 138 may be thesame angle as the two opposing sides of the front major surface 140. Inanother embodiment the angles may be different.

The light emitted by the configurations shown in FIGS. 4A-4C may beemitted at different angles relative to the optical axis 114 compared tothe diffuse bright field illumination sub-system 105 depicted in FIG. 1.

The diffuse bright field illumination sub-system 105 with theseconfigurations is a diffuse bright field illumination system providinguniform illumination for barcodes applied to a concave/convex surface.

As discussed, the optical substrate 122 may be positioned between theone or more light sources 120. For example, as shown in FIGS. 1 and 2A,the one or more light sources 120 may be located along an edge 186 ofthe optical substrate 122 that is located between the front majorsurface 140 and the back major surface 138. The one or more lightsources 120 introduce light into the edge 186 of the optical substrate.In FIG. 1, light is introduced from the one or more light sources 120into the optical substrate 122 in a direction generally perpendicular tothe optical axis 114 and generally towards the optical axis 114.

For example, as shown in FIG. 3B the one or more light sources 120 maybe located along an edge of the back major surface 138 of the opticalsubstrate 122 with the chamfered edge 125 reflecting illumination in adirection between the front major surface 140 and the back major surface138 in a direction generally perpendicular to the optical axis 114 andgenerally towards the optical axis 114.

The center of the optical substrate 122 may include an opening 133 (asshown in FIG. 2E) or an aperture 132 (as shown in FIGS. 2A-2D) throughwhich objects (such as a barcode) within the field of view 106 may bevisible to the optic system 104 and the photo sensor array 102. As shownin FIGS. 2A-2D, the aperture 132 may be rectangular and of sufficientsize such that the optical substrate 122 is not within the field of view106 of the camera. As shown in FIG. 2E, the optical substrate 122 mayhave an approximately annular shape where the center opening 133 of theannular optical substrate 122 is circular and of sufficient size suchthat the optical substrate 122 is not within the field of view 106 ofthe camera.

With continued reference to FIG. 2E, the optical substrate 122 may havean annular shape that includes an outer edge 186 and an inner edge 187.In the depicted embodiment multiple light sources 120 a-d may bepositioned on the back major surface 138 of the optical substrate 122and may input light into the optical substrate 122 through the backmajor surface 138. For example, the light sources 120 a-d may bepositioned as shown in FIG. 3B or 3C. In FIGS. 3B and 3C, the lightsources 120 a-d input light through the back major surface 138 in adirection approximately parallel to the optical axis 114. After enteringthe optical substrate 122, the light is reflected by a chamfered edge125 of the outer edge 186. The chamfered edge 125 is configured toreflect light onto a path relatively perpendicular to the optical axis114. In another embodiment (not shown) in which the optical substratehas an annular shape, light enters the optical substrate 122 through theoutside edge 186 in a direction approximately perpendicular to theoptical axis 114.

To prevent the optical substrate 122 from functioning simply as a lightpipe or light guide, the optical substrate 122 includes one or moreextraction features 142 configured to extract light from the opticalsubstrate 122 and into the field of view 106. The extraction features142 may introduce a variation in the index of refraction (i.e., alocation of a non-uniform index of refraction) of the optical substrate122. Each extraction feature 142 functions to disrupt the total internalreflection of the propagating light that is incident on the extractionfeature.

As described above with respect to FIGS. 2A and 2D, the illumination 190a-d directed into the edge 186 of the optical substrate 122 generallypropagates through the optical substrate 122 due to total internalreflection. Any illumination 190 a-d that is incident on the one or moreextraction features 142 may be diffused with a first portion beingdiffused at an angle such that the illumination continues propagatingwithin the optical substrate 122 (based on total internal reflection)and a second portion that may be diffused at an angle (i.e., an escapeangle) that overcomes total internal reflection, “escapes” the surface,and is directed into the field of view 106.

The extraction of illumination through the front major surfaceintroduced by the extraction features 142 may comprise at least one of:i) one or more particles within the optical substrate 122; ii) a planarsurface within the optical substrate 122; iii) a variation in thesurface topography of the back major surface 138; and iv) a variation inthe surface topography of the front major surface 140. For example, inFIGS. 3A and 3B, the optical substrate 122 is embedded with particleshaving an index of refraction greater or less than the optical substrate122. As light travels from the edge 186 of the optical substrate 122through total internal reflection towards a center of the opticalsubstrate 122, the particles disrupt the total internal reflection ofthe light, causing a portion of the propagating light to exit throughthe front major surface 140.

The extraction features 142 may be configured to extract light in adefined intensity profile over the front major surface 140, such as auniform intensity profile, and/or a defined light ray angledistribution. In FIG. 3A, the one or more extraction features 142 aredistributed non-uniformly throughout the optical substrate 122. In thisexample, the one or more extraction features 142 are distributedthroughout the optical substrate such that light is uniformly emittedfrom the front major surface 140 of the optical substrate 122. Forexample, the extraction features 142 may be spread throughout theoptical substrate 122 in concentrations that increase with distance fromthe at least one light source 120.

Alternatively, in FIG. 3B, the one or more extraction features 142 maybe distributed uniformly or non-uniformly throughout the opticalsubstrate. In this example, the one or more extraction features aredistributed throughout the optical substrate such that light is notuniformly emitted from the front major surface 140 of the opticalsubstrate 122. Instead the light is emitted from the front major surface140 in a desired intensity pattern. While not shown, the one or moreextraction features 142 may be distributed in alternative patterns thatresult in the light being emitted from the front major surface 140 ofthe optical substrate 122 having a more structured appearance (i.e., anon-uniform intensity pattern).

As shown in FIGS. 3C and 3E, the extraction features 142 may alsocomprise a surface variation in the topography of at least one of thefront major surface 140 and the back major surface 138. In the depictedembodiment of FIG. 3C, the one or more extraction features 142 comprisevariations in the back major surface 138 of the optical substrate 122.In this example, the front major surface 140 of the optical substrate122 is smooth and planar, while the back major surface 138 includes atopography of convex and concave indentations and protrusions. In thedepicted embodiment of FIG. 3E, both the back major surface 138 and thefront major surface 140 include extraction features 142 comprisingconvex and concave indentations and protrusions.

These embodiments are configured to result in a homogenous output oflight from the front major surface 140.

The convex and concave indentations and protrusions may be: i)extraction features 142 with specific optical properties, such as microlenses formed by, for example, molding or laser cutting; or ii)extraction features 142 with no specific optical properties (i.e.,random) such as a roughened surface formed by any of a textured tool orsanding of the surface after molding. Further, the shape, density, orother optical properties of the extraction features 142 may increasewith distance from the light source 120 a-d in order to produce uniformillumination from the optical substrate.

Referring to FIGS. 3D and 3F, the one or more extraction features 142comprise a surface within the optical substrate 122. In this embodiment,the optical substrate 122 may be made of two different materials 546,548. These materials 546, 548 may have different indices of refraction,and they may be in contact with one another. In FIG. 3E, the contact isalong a surface forming the one or more extraction features 142. In FIG.3F the contact is along a surface of convex and concave shapes, eitherpatterned or random. Refraction at the one or more extraction features142 directs illumination towards the front major surface 140 of theoptical substrate 122 at an angle where the illumination exits the frontmajor surface 140 towards the field of view 106. As a variation to theseembodiments, the materials 546, 548 may have the same index ofrefraction, but a material with a different index of refraction may besandwiched between the materials 546, 548 at the non-planar contactsurface.

As will be understood by one of ordinary skill in the art, the opticalsubstrate 122 and the extraction features 142 are not limited to thesedescribed embodiments. Other embodiments of the optical substrate 122including extraction features 142 are also within the scope of thepresent disclosure.

In all of these embodiments, to further increase the quantity ofillumination exiting through the front major surface 140, a reflectivebacking 144 may be applied to the back major surface 138. The reflectivebacking 144 may be applied uniformly such that it covers the entire backmajor surface 138. The reflective backing 144 reduces the amount oflight that escapes through the back major surface 138 by reflectinglight back inward into the optical substrate 122. In another embodiment,a cladding film (not shown) having an index of refraction less than theindex of refraction of the optical substrate 122 is adjacent the backmajor surface 138. The cladding film reduces the amount of light thatescapes by reflecting light inward through total internal reflection.Similarly, all edges and surfaces of the optical substrate 122 (exceptfor the edges 186 where the one or more light sources 120 a-d projectillumination into the optical substrate 122) may also be coated with areflective backing 144.

Referring again to FIG. 1, the dark field illumination sub-system (i.e.,a close-range illumination sub-system) 152 may include one or more darkfield illumination sources 152 a-b. Light from the one or more darkfield illumination sources 152 a-b may be emitted at an angle closer toperpendicular to the optical axis 114 than the light from either of thedirect bright field illumination sub-system 108 or the diffuse brightfield illumination sub-system 105.

Each of the at least one or more dark field illumination sources 152 a-bmay comprise an LED. Additional optics 154 a-b may also be associatedwith the one or more dark field illumination sources 152 a-b to directillumination to the field of view 106. The additional optics 154 a-b mayutilize refraction, diffusion, prismatic effect, and/or total internalreflection to direct dark field illumination 156 a-b into the field ofview 106.

The dark field illumination 156 a-b emitted by the at least one darkfield illumination source 152 a-b may be emitted at an angle no morethan 45° from a plane perpendicular to the optical axis 114.

The dark field illumination 156 a-b may be optimal for reading a barcodethat is located within the close zone 158 of the field of view 106.However, the dark field illumination 156 a-b may not be sufficientlybright to provide optimal illumination for reading a barcode that islocated farther away from the barcode reader 100 than from the closezone ending boundary 162.

In the embodiment shown in FIG. 1, the dark field illumination sources152 a-b may be mounted on circuit boards at the sides of the barcodereader housing 101. The optics 154 a-b may comprise lenses, gratings, ordiffusion material that diffuses the illumination 156 a-b from the darkfield illumination sources 152 a-b.

With reference to FIG. 5, an alternative embodiment of the barcodereader 100 is explained. In this embodiment, at least one tertiary lightsource 152 a-b is mounted on a circuit board 792 that is substantiallyperpendicular to the optical axis 114. Illumination 776 a-b from the atleast one tertiary light source 152 a-b is directed substantiallyparallel to the optical axis 114 toward chamfered ends 778 a-b. Morespecifically, at least one tertiary light source 152 a-b may projectillumination 776 a-b into light pipes 788 a-b, which use total internalreflection to propagate the illumination 776 a-b toward the chamferedends 778 a-b. The chamfered ends 778 a-b are used to re-direct theillumination 776 a-b toward the field of view 106 at the desired angle.

The light pipes 788 a-b may comprise chamfered ends 778 a-b. Thesechamfered ends 778 a-b may serve as the prism optics that re-directs theillumination 776 a-b toward the field of view. Each of the chamferedends 778 a-b may be angled such that total internal reflection redirectsthe illumination 776 a-b at a non-zero angle (e.g., 45°) relative to theplane that is perpendicular to the optical axis 114. The illumination776 a-b may exit the light pipes 788 a-b through the side facing theoptical axis 114. It should be appreciated that the light pipes 788 a-bare shown in cross section and may be on each side of the camera (i.e.,all four sides, left, right, top, bottom) or may even form an annularring around the field of view of the camera.

Referring to FIG. 6, another embodiment of the barcode reader 100 isshown. In this embodiment, the optical substrate 880 forms a protectivewindow over optical substrate 122 and replaces the optics 110 a-b, and154 a-b of FIG. 1. In this example, the at least one tertiary lightsource 152 comprises LEDs positioned behind diffusion regions 884 a-b ofthe optical substrate 880. The diffusion regions 884 a-b direct darkfield illumination 856 a-b from the LEDs into the field of view 106. Thecurved regions 882 a-b provide structural support for the diffusionregions 884 a-b as well as focus the illumination projected fromsecondary illumination sources 108 a, 108 b, or secondary illuminationsources 115 a, 115 b.

Referring to FIG. 7, another embodiment of the barcode reader 100 isshown. In this embodiment, the optical substrate 881 forms a protectivewindow over optical substrate 122 and replaces the optics 110 a-b ofFIG. 1.

As shown in FIG. 8A, the diffusion region 884 may include an opticalsubstrate into which illumination 815 a-b is projected by two side fireilluminators 813 a-b. The illumination 815 a-b is internally reflectedwithin the substrate 811 and extracted as diffuse illumination 156 fromthe optical substrate 811. The optical substrate 811 may have any of thesame characteristics and extraction features as the optical substrate122 as described with respect to FIGS. 1, 2A-2D, 3A-3F and 4A-4C as wellas reflective coatings 144 such that illumination propagates between afront major surface 140 and a back major surface 138 of the opticalsubstrate 811 and is extracted through the front major surface 140 asillumination 156.

As shown in FIG. 8B, the diffusion region 884 may include an opticalsubstrate 821 into which illumination 825 a-b is projected through theback major surface by two illuminators 819 a-b. The illumination 825 a-bis reflected from chamfered surfaces such that it propagates between thefront major surface 140 and the back major surface 138 and is extractedas diffuse illumination 156 from the optical substrate 821. As withoptical substrate 811, the optical substrate 821 may have any of thecharacteristics, and extraction features, as the optical substrate 122as described with respect to FIGS. 1, 2A-2D, 3A-3F, and 4A-4C, as wellas reflective coatings 144 such that illumination propagates between afront major surface 140 and a back major surface 138 of the opticalsubstrate 821 and is extracted through the front major surface asillumination 156.

The diffusion regions 884 a-b direct dark field illumination 856 a-bfrom the LEDs into the field of view 106. The curved regions 882 a-bprovide structural support for and focus the illumination projected fromsecondary illumination sources 108 a, 108 b or secondary illuminationsources 115 a, 115 b. Posts 883 a and 883 b provide structural supportfor diffusion region 884 a-b and prevent illumination from entering intothe curved regions 882 a-b.

The previous discussion has been directed to a barcode reader thatincludes three different light sources: at least one secondary lightsource (a bright field illumination system, positioned as any of: i)closer to (i.e., in front of) the field of view than to the tertiarylight sources; ii) behind the tertiary light sources but in front of thediffuse bright field illumination sources; or iii) behind the diffusebright field illumination sources and the optical substrate 122, behindat least one light source (i.e., a diffuse bright field illuminationsystem), and behind at least one tertiary light source (i.e., a darkfield illumination system).

It should also be appreciated that each of these illumination sourcesmay generate illumination with different characteristics. For example,the diffuse bright field illumination may be white LEDs (i.e.,illumination with intensity across a wide spectrum of wave lengths)while the tertiary light source and the secondary light source may bered LEDs (i.e., intensity at 660 nm).

FIG. 9A is a block diagram representative of a barcode reader, such asbarcode reader 100, including an image capture control and decode system107 in combination with an image sensor system package 111, anillumination system 103, and various input/output (I/O) peripheralsystems 113 in accordance with one embodiment of the present disclosure.The image sensor system package 111 and the image capture control anddecode system 107 may be included in two separate packages, each ofwhich may include one or more silicon dies that may include: i) aprocessor; ii) hardware circuits including digital signal processingand/or gate logic, and iii) memory. The processor may be a generalpurpose single or multi-die microprocessor (e.g., an ARM), a specialpurpose microprocessor (e.g., a digital signal processor (DSP)), amicrocontroller, a programmable gate array, etc. The processor may bereferred to as a central processing unit (CPU). The memory may be anycombination of non-volatile memory or storage and volatile memory orstorage. The non-volatile memory may include a combination of read onlymemory (ROM) and/or flash memory.

Illumination Systems

The illumination system 103 includes a plurality of illuminationsub-systems 930 a-c, each having different illumination characteristics.Some examples of different illumination characteristics include theangle of illumination with respect to an optical axis, the intensity ofillumination, the wavelength of illumination, diffusion characteristicsof the illumination, the illumination profile which may include theintensity of the illumination within a two dimensional plane spaced fromthe barcode reader 100 or the three dimensional shape within the fieldof view at which illumination emitted by the illumination sub-system hasa predetermined intensity, etc.

The plurality of illumination sub-systems 930 a-c may include a directbright field illumination system, for example, similar to the directbright field illumination sub-system 108 shown in FIG. 1, a diffusebright field illumination sub-system, for example, similar to thediffuse bright field illumination sub-system 105 shown in FIG. 1, and adark field illumination sub-system, for example, similar to the darkfield illumination sub-system 152 shown in FIG. 1.

It should be noted that the number of illumination sub-systems 930 a-cshown in FIG. 9A and the characteristics of each illumination sub-systemdisclosed herein are provided only as an example. In an alternativeconfiguration, a barcode reader may include more than three (or anynumber of) different illumination sub-systems, and the illuminationsub-systems may provide illumination having different illuminationcharacteristics (e.g., by changing the intensity, wavelength, angle,diffusion characteristics of the illumination, illumination profilecharacteristics or the like).

I/O Peripheral Systems

The I/O peripheral systems 113 may include a user interface comprisinginput control 938 and/or a display 940. The input control 938 mayinclude a trigger switch 942, a keypad 944, and/or a touch panel 945,such as a touch screen over the display 940. In addition, the barcodereader 100 may have one or more output devices that convey informationto a user. Such output devices may include the touch panel 945, whichmay be a touch screen, a speaker 943, a vibrator 947, and/or one or morecomponents that illuminate in a manner visible to a user, such as one ormore LEDs 949.

The I/O peripheral systems 113 may further include one or morecommunication interfaces 908. The communication interfaces 908 mayinclude a wireless LAN interface 908 a and a point-to-point interface908 b which may be a wireless point-to-point interface and/or ahardwired point-to-point interface.

The wireless LAN interface 908 a may permit the barcode reader 100 to bean addressable endpoint in a wireless local area network and communicatewith a host device through the LAN using, for example, TransmissionControl Protocol/Internet Protocol (TCP/IP) or the like.

The wireless point-to-point interface(s) 908 b may be, for example, aBluetooth® interface to enable the barcode reader 100 to establish awireless point-to-point communication link with, and communicate overthe wireless communication link with, a host device (i.e., a hostcomputer).

The hardwired point-to-point interface(s) 908 b may comprise a UniversalAsynchronous Receiver/Transmitter (UART) or a Universal Serial Bus (USB)in each case to enable the barcode reader 100 to establish apoint-to-point connection with a host device using a multi-conductordata interface.

Image Capture Control and Decode System

The image capture control and decode system 107 may include: i) aprocessor 948; ii) a memory 952; and iii) hardware circuits 950 forcoupling to, and driving operation of, each of the illumination system103, the I/O peripheral systems 113, and the image sensor system package111.

The processor 948, as described, may be a general purpose single ormulti-die microprocessor (e.g., an ARM), a special purposemicroprocessor (e.g., a digital signal processor (DSP)), amicrocontroller, a programmable gate array, etc. The processor 948 maybe referred to as a central processing unit (CPU). Although just asingle processor 948 is shown in FIG. 9A, in an alternativeconfiguration, a combination of processors (e.g., an ARM and DSP) may beused.

The hardware circuits 950 provide the interface between the imagecapture control and decode system 107 and each of the illuminationsystem 103, the I/O peripheral systems 113, and the image sensor systempackage 111. The hardware circuits 950 may further include illuminationlogic 954 and pre-processing circuits 951 a-n, each of which will bedescribed in more detail herein.

The memory 952, as described, may be any combination of non-volatilememory or storage and volatile memory or storage. The memory 952 mayinclude an image buffer 970, an image processing module 979, a decoder980, and an image capture module 962. These components may be stored inany combination of volatile and non-volatile memory. Some modules may bestored in both volatile and non-volatile memory, for example, withpermanent storage of the module in non-volatile memory and a temporarycopy stored in volatile memory for execution by the processor 948. Inaddition to, or as an alternative to, these modules, the memory 952 maystore any number of other modules including but not limited to those setforth in the patent applications incorporated by reference in thisdisclosure. A more detailed description of the image capture control anddecode system 107 is included herein.

Image Sensor System Package

The image sensor system package 111 may include: i) a two-dimensionalphoto sensor array 102 onto which illumination from the field of view106 of the barcode reader 100 (FIG. 1) is focused by the optic system104; ii) hardware gate logic 941 implementing one or more pre-processingcircuits 965 a-n; iii) volatile memory or storage such as random accessmemory implementing an image buffer 963; iv) hardware gate logicimplementing wide bus logic 955 for transferring each image framecaptured by the photo sensor array 102 to the hardware gate logic 941(or the image buffer 963); and v) control circuitry 939 which mayinclude a combination of gate logic, volatile memory or storage, aprocessor executing code stored in the memory implementing control ofthe photo sensor array 102 (image read-out), the wide bus logic 955, thehardware gate logic 941; the image buffer 963, and transfer of imagedata records to the image capture control and decode system 107.

Photo Sensor Array

The photo sensor array 102 may comprise a two-dimensional rollingshutter array of pixels with each pixel comprising an activephotosensitive region capable of measuring or quantifying the intensityof illumination incident on the pixel fabricated, for example, usingknown complementary metal oxide semiconductor (CMOS) sensor technology.Each pixel may be a photodiode which accumulates charge over theduration of an exposure period. Prior to commencement of the exposureperiod the photodiode may be coupled to ground to dissipate anaccumulated charge and the exposure period for the pixel may commencewhen the photodiode is de-coupled from ground so that a chargeaccumulates in proportion to the intensity of illumination incident onthe pixel. The charge on the photodiode continues to accumulate so longas illumination is incident on the photodiode. The exposure period endswhen the accumulated charge is measured by an analog to digital (A/D)converter.

In one embodiment, the photodiode may couple to the input of an A/Dconverter when the control circuitry 939 generates a read signal and,upon coupled of the photodiode to the A/D converter, the A/D convertergenerates a digital value representative of the accumulated charge atthe time the photodiode is coupled to the A/D converter which is inputto a register of the wide bus logic 955 for transfer to thepre-processing circuits 965 a-n (or the image buffer 963).

In another embodiment, the photodiode may be coupled to the input of anA/D converter prior to the end of the exposure period. In thisembodiment, the A/D converter may be continually making a digital valuerepresentative of the accumulating charge available at its output portwith that digital value continually increasing as charge accumulates onthe photodiode (i.e. periodically updating the digital value torepresent the increasing voltage as charge accumulates on thephotodiode). In this embodiment when the control circuitry 939 generatesa read signal the then current digital value (at the time of the readsignal) is read or input to a register of the wide bus logic 955 fortransfer to the pre-processing circuits 965 a-n (or the image buffer963).

In order to improve sensitivity of the photo sensor array 102, thepixels do not include a masked charge storage region associated witheach photosensitive region for temporarily holding accumulated chargefrom the photodiode region prior to coupling the charge from thephotodiode to the A/D converter 987. Directly coupling thephotosensitive region to the A/D converter 987 means that there is nocharge storage region separate from the photodiode on which charge isaccumulating. Stated another way, in neither of the foregoingembodiments, is the accumulated charge on the photodiode buffered, as ananalog charge or otherwise, prior to being coupled to the A/D converter.Stated in yet another way, in neither of the foregoing embodiments isaccumulation of the charge stopped, or the accumulated charge otherwisemade static (no more accumulation) prior to being coupled to the A/Dconverter.

FIG. 9B depicts a photo sensor array 102 with A/D converters 987 and animage capture operation in accordance with one embodiment of the presentdisclosure. The photo sensor array 102 may comprise a plurality of rowsof pixels 982 a-e and one A/D converter 987 per column of pixels suchthat each pixel in an entire row may have a simultaneous exposure periodend time and may be simultaneously coupled to a correspondinganalog-to-digital (A/D) converter 987 which generates the digital valueat the end of the exposure period applicable to the pixel.

In the exemplary embodiment wherein there is one A/D converter percolumn, the photo sensor array 102 may be operative such that exposureof the rows of pixels 982 a-e is initiated, and subsequently terminated,sequentially from the first of the plurality of rows (e.g., row 982 a)to the last of the plurality of rows (e.g., row 982 e), one row at atime from either the top of the image sensor array 102 to the bottom ofthe image sensor array 102 or from a top row within a cropped window ofthe image sensor array 102 to the bottom row within the cropped windowof the image sensor array 102.

More specifically, using row 982 a at a top of the photo sensor array102 as an example, the exposure period begins at a start of an exposureperiod 984 a and the end of the exposure period 985 a. The start of theexposure period 984 a begins when the photosensitive region 983 of eachpixel within the row is contacted with the ground 986 to dissipate anycharge which may have accumulated on the photosensitive region 983 priorto the beginning of the exposure period. The end of the exposure period985 a is when the photosensitive region 983 of each pixel in the row iscoupled directly to an A/D converter 987 and the A/D converter 987generates a digital intensity value (digital value) representative ofthe accumulated charge. The digital intensity value for each pixelwithin the row may be written to a register of the wide bus logic 955for output to the pre-processing circuits 965 a-n or directly to theimage buffer 963.

It should be appreciated that one row of pixels at a time may besimultaneously exposed (simultaneous commencement and subsequentsimultaneous termination of an exposure period). The next row of pixelsmay then have a simultaneous exposure period that does not requiretermination (e.g. coupling of each pixel to an A/D converter) untilafter the A/D converters have completed operation on the previous row.The time required for an A/D converter to produce a digital valuerepresentative of accumulated charge may be referred to as the A/Dconverter cycle time. When the quantity of A/D converters is equal tothe number of columns the minimum read-out time for all rows would bethe number of rows multiplied by the A/D converter cycle time.

In more detail, the start of exposure for each row is initiated at apredetermined amount of time 988 following the start of exposure for theimmediately preceding row and the end of exposure for each row occurs atthe predetermined amount of time 988 following the end of exposure forthe immediately preceding row. The predetermined amount of time 988 maybe greater than the time required for each pixel in the row to becoupled to its A/D converter 987, the intensity value to be written tothe register of the wide bus logic 955, and the register value to beoutput to the pre-processing circuits 965 a-n or written to the imagebuffer 963. In the exemplary embodiment, each row of pixels an exposureperiod long enough, and read-out fast enough, such that the exposureperiod is initiated for the last row of pixels 982 e of the photo sensorarray 102 prior to the end of the exposure period (i.e., when read-outcommences) for the first row of pixels 982 a of the photo sensor array102 such that a time period 989 exists when all rows are beingsimultaneously exposed.

As such, the total exposure period for the array of pixels comprises: i)a first period 990 being the time between when exposure of the first rowof the array is initiated and exposure of the last row of the array isinitiated; ii) a second period 989 being the time when all rows arebeing simultaneously exposed; and iii) a third period 991 being the timebetween when read-out of the first row of the array is initiated andread-out of the last row is initiated (i.e., the time between whenexposure of the first row ends and exposure of the last row of the arrayends). In one embodiment, the total exposure period for any particularrow remains less than 20 ms. In another embodiment, the total periodfrom start of exposure for the first row and end of exposure for thelast row may be less than 20 ms.

In one embodiment, the exposure period 981 may be expressed as aquantity of rows of the image sensor array. The total exposure time maybe expressed as the number of rows multiplied by the time 988 requiredto read-out a row. Stated another way, when the exposure period 981 isexpressed as a quantity of rows, the numerical value for the exposureperiod is the quantity of rows between the row that is then currentlycommencing its exposure period and the row that is then currently beingread-out (ending exposure period). When the exposure period is veryshort (i.e., a quantity of rows less than the total quantity of rows inthe array) read-out of the rows that first started exposure (for exampleat the top of the array if exposure runs from the top to the bottom)commences before rows at the bottom of the array begin exposure.However, as described above, in the exemplary embodiment, read-out isvery fast such that the exposure period, when expressed as a quantity ofrows, will be a numerical value greater than the total number of rows inthe photo sensor array 102.

While FIG. 9B depicts one A/D converter 987 per column, it should beappreciated that other configurations may include fewer A/D converters987 (fewer than one (A/D converter 987 per column) or more than one A/Dconverter 987 per column. The quantity of A/D converters may define thequantity of pixels for which the exposure period may simultaneously end(e.g. the quantity of pixels for which the accumulated charge may besimultaneously converted to a corresponding digital value).

As another example, if the quantity of A/D converters is equal to halfthe number of columns, one-half of a row of pixels may be simultaneouslyexposed. The next one-half row of pixels may then have a simultaneousexposure period that does not require termination until after the A/Dconverters have completed operation on the previous one-half row. If thequantity of A/D converters is equal to one-half the number of columns itwould require two A/D converter read-out cycles to read-out each row andthe minimum read-out time for all rows would be the number of rowsmultiplied by two and then multiplied by the A/D converter cycle time.

Similarly, as depicted in FIG. 9C, the quantity of A/D converters 987 aand 987 b may be equal to twice the number of columns (arranged in twobanks of A/D converters 987 a and 987 b). In this exemplary embodiment,there are a sufficient quantity of A/D converters to read-out two rowssimultaneously. Each bank of A/D converters 987 a and 987 b is connectedto, and operates on, every other alternating row of pixels. As such, thephoto sensor array 102 may be operative such that exposure of the rowsof pixels 982 a-e is initiated, and subsequently terminated,sequentially in two-row groups from the first group of rows (e.g., row982 a-b) to the last of the plurality of rows (e.g., group includingrows 982 d-e).

More specifically, using rows 982 a and 982 b at as top of the photosensor array 102 as an example, the exposure period begins at a start ofan exposure period 984 a and the end of the exposure period 985 a. Thestart of the exposure period 984 a begins when the photosensitive region983 of each pixel within the two rows is contacted with the ground 986to dissipate any charge which may have accumulated on the photosensitiveregion 983 prior to the beginning of the exposure period. The end of theexposure period 985 a is when the photosensitive region 983 of eachpixel in the two rows is coupled directly to an A/D converter 987 a, 987b and the A/D converter 987 to generate a digital intensity value(digital value) representative of the accumulated charge. The digitalintensity value for each pixel within the two rows may be written to aregister of the wide bus logic 955 for output to the pre-processingcircuits 965 a-n or directly to the image buffer 963.

It should be appreciated that in this embodiment two rows of pixels at atime may be simultaneously exposed (simultaneous commencement andsubsequent simultaneous termination of an exposure period). The nextgroup of two rows of pixels may then have a simultaneous exposure periodthat does not require termination (e.g. coupling of each pixel to an A/Dconverter) until after the A/D converters have completed operation onthe previous group of two rows. Again, the time required for an A/Dconverter to produce a digital value representative of accumulatedcharge may be referred to as the A/D converter cycle time. When thequantity of A/D converters is equal to twice the number of columns theminimum read-out time for all rows would be one half the number of rowsmultiplied by the A/D converter cycle time.

In more detail, the start of exposure for each group of two rows isinitiated at a predetermined amount of time 988 following the start ofexposure for the immediately preceding group of two rows and the end ofexposure for each group of two rows occurs at the predetermined amountof time 988 following the end of exposure for the immediately precedinggroup of two rows.

The predetermined amount of time 988 may be greater than the timerequired for each pixel in the group of two rows to be coupled to itsA/D converter 987, the intensity value to be written to the register ofthe wide bus logic 955, and the register value to be output to thepre-processing circuits 965 a-n or written to the image buffer 963. Inthe exemplary embodiment, each pixel within the group of two rows issubject to an exposure period long enough, and read-out fast enough,such that the exposure period is initiated for the last group of tworows of pixels 982 d-e of the photo sensor array 102 prior to the end ofthe exposure period (i.e., when read-out commences) for the first groupof two rows of pixels 982 a-b of the photo sensor array 102 such that atime period 989 exists when all rows are being simultaneously exposed.

As such, the total exposure period for the array of pixels comprises: i)a first period 990 being the time between when exposure of the firstgroup of two rows of the array is initiated and exposure of the lastgroup of two rows of the array is initiated; ii) a second period 989being the time when all rows are being simultaneously exposed; and iii)a third period 991 being the time between when read-out of the firstgroup of two rows of the array is initiated and read-out of the lastgroup of two rows is initiated (i.e., the time between when exposure ofthe first group of two rows ends and exposure of the last group of tworows of the array ends).

In one embodiment, the total exposure period for any particular group oftwo rows remains less than 20 ms. Alternatively, the total period fromstart of exposure for the first group of two rows and end of exposurefor the last group of two rows may be less than 20 ms.

Windowing, Binning, Sub Sampling (Read-Out Level)

The term image frame, as used herein, may be a full image frame, abinned image frame, a sub-sampled image frame, or a window of any of afull, binned, or sub-sampled image frame.

As used herein, the term “full image frame” refers to an image framethat is captured when an entire photo sensor array 102 is exposed andread-out. Thus, a full image frame may include pixels corresponding toall of the photo sensors in the photo sensor array 102.

As used herein, the term “binned image frame” refers to an image framethat is captured by simultaneously combining the photodiodes formultiple adjacent pixels to a single A/C converter (effectively creatinga single pixel with a larger photosensitive region comprising thephotosensitive regions of the combined pixels, but an overall lowerresolution for the image frame). Common binning may include combininggroups of two adjacent pixels horizontally, groups of two adjacentpixels vertically, and two-by-two groups of pixels as depicted in FIG.12A. The resolution values of the image capture parameter values for animage frame that is to be captured as a binned image frame will definethe binning (how adjacent pixels are to be grouped).

As used herein the term “sub-sampled image frame” refers to an imageframe that is captured at a lower resolution utilizing a pattern offewer than all of the pixels applied across the full photo sensor, forexample every second pixel or every fourth pixel. The used pixels areread-out while the un-used pixels are not-read-out or the data isignored. The resolution values of the image capture parameter values foran image frame that is to be captured as a sub-sampled image frame willdefine the sub-sampling ratio of pixels which are read and used versusun-used pixels.

As used herein the term “a window of an image frame” refers to a portionof a full image frame, a binned image frame or a sub-sampled image framethat is smaller than the full photo sensor array image, either byvertical cropping, horizontal cropping, or both. The portions of thepixels outside of the cropping may not be read-out. The image captureparameter values for an image frame that is to be captured as a windowedimage frame (full, binned, or sub-sampled) will define the horizontaland vertical cropping, as applicable.

It should be appreciated that binning, subsampling, and windowing may beperformed by the image sensor array 102 at read-out such that theresulting image frame (full, binned, sub-sampled, and/or windowed) isthe image frame input to the pre-processing circuits 965 a-n.

Wide Bus Logic

To enable digital values representative of illumination on pixels to betransferred very quickly from the A/D converters 987 to thepre-processing circuits 965 a-n (or written directly to the image buffer963) wide bus logic 955 may transfer the digital intensity values fromall A/D converters 987 to the pre-processing circuits 965 a-n (or theimage buffer 963) in parallel (e.g. the same clocking cycles transferall digital intensity values from all A/D converters 987 to thepre-processing circuits 965 a-n (or the image buffer 963)simultaneously).

Stated another way, the wide bus logic 955 may include transfer logicmodules, each implementing a channel for transfer of a digital intensityvalue from an A/D converter 987 to the pre-processing circuits 965 a-n(or the image buffer 963), with the quantity of transfer logic modulesbeing equal to the quantity of A/D converters, and with each distincttransfer logic module being coupled to the output of one distinct A/Dconverter. Stated yet another way, the wide bus logic 955 may implementa digital intensity value transfer bus (from the A/D converters 986 tothe pre-processing circuits 965 a-n (or the image buffer 963) that is aswide as the number of A/D converters.

Alternatively, the width of the wide bus logic 955 may be 50% of thenumber of A/D converters, in which case it would take two bus cycles totransfer all digital intensity values from all A/D converters to thepre-processing circuits 965 a-n or to the image buffer 963.Alternatively, the width of the wide bus logic 955 may be 25% of thenumber of columns, in which case it would take four bus cycles totransfer all digital intensity values from all A/D converters to thepre-processing circuits 965 a-n or to the image buffer 963. It should benoted that the width of the wide bus logic 955 may be any percentage ofthe number of columns of the photo sensor array. However, if an entirerow of pixels is to undergo a simultaneous exposure period utilizing aquantity of A/D converters equal to the number of pixels in the row, butthe bus logic 955 is not sufficient to transfer digital intensity valuesfrom all A/D converters simultaneously, the bus logic 955 may includefirst-in-first-out (FIFO) buffers (one FIFO buffer for each A/Dconverter) for buffering digital intensity values prior to transfer tothe pre-processing circuits 965 a-n or to the image buffer 963.

Pre-Processing Circuits

Returning to FIG. 9A, the hardware gate logic 941 includes multiplepre-processing circuits 965 a-n. The pre-processing circuits 965 a-n mayperform operations such as convolution, binning, sub-sampling, croppingand other image processing functions on an image frame (full, binned,sub-sampled, and/or cropped) to generate one or more image data record967 a-n, each of which is derived from the image frame or an image datarecord that was previously derived from the image frame.

Each pre-processing circuit 965 a-n may receive as input either: i) a animage frame (full, binned, sub-sampled, and/or cropped) receiveddirectly from the photo sensor array 102 by way of the wide bus logic955; or ii) an image data record 967 a-n from the image buffer 963 whichis the result of a different pre-processing circuit 965 a-n previouslyoperating on an image frame (full, binned, sub-sampled, and/or cropped)received directly from the photo sensor array 102 by way of the wide buslogic 955.

It should be noted that one image frame (full, binned, sub-sampled,and/or cropped) may be input to multiple pre-processing circuits 965 a-nresulting in multiple image data records 967 a-n being written to theimage buffer 963 for the same frame of image data. Further, for a burstof multiple image frames (described herein), each image frame (full,binned, sub-sampled, and/or cropped) may be input to the same one ormore pre-processing circuits 965 a-n or permutations of different imageframes of the burst may be input to different subsets of pre-processingcircuits 965 a-n, each subset including one or more pre-processingcircuits 965 a-n.

It should also be noted that one of the pre-processing circuits 965 maysimply write the image frame (full, binned, sub-sampled, and/or cropped)to the image buffer 963 as an image data record 967 without performingsubstantive image processing (e.g. writing the intensity values receivedfrom the A/D converters for the image frame to the image buffer).

Referring briefly to FIG. 14, image processing functions that may beperformed by any of the image pre-processing circuits 965 a-n and theimage data records 967 a-n derived from each image frame (whether full,binned, sub-sampled, and/or windowed and/or cropped) include: i)transfer of the image frame or a window within an image frame (full,binned, cropped, or sub-sampled) as a resulting image data record 967a-n to the image buffer 963; ii) cropping of an image frame (full,binned, cropped, or sub-sampled) and transfer of the resulting imagedata record 967 a-n to the image buffer 963; iii) binning an image frame(full, binned, cropped, or sub-sampled) and transfer of the resultingimage data record 967 a-n to the image buffer 963; iv) subsampling animage frame (full, binned, cropped, or sub-sampled) and transfer of theresulting image data record 967 a-n to the image buffer 963; v)generating a rotation of an image frame (full, binned, cropped, orsub-sampled) and transfer of the resulting image data record 967 a-n tothe image buffer 963; vi) generating a convolution of an image frame(full, binned, cropped, or sub-sampled) and transfer of the resultingimage data record 967 a-n to the image buffer 963; and vii) generating adouble convolution which is a second sequential convolution performed onthe result of a previously performed convolution of a an image frame(full, binned, cropped, or sub-sampled) and transfer of the resultingimage data record 967 a-n to the image buffer 963. Each sequentialconvolution utilizes a different distinct kernel. Each of these imageprocessing operations is described in more detail herein.

The pre-processing circuits 965 a-n may be implemented in hardware gatelogic 941 to provide for image processing very quickly such thatprocessing by a pre-processing circuit 965 a-n, and thereby generating,and storing in the image buffer 963, one or more image data records 967a-n may be performed during the limited amount of time that the imageframe is being read from the photo sensor array 102 such that raw pixeldata (i.e., digital intensity values from the A/D converters coupled tothe image sensor array) do not need to be stored in memory (other thansimple FIFO buffers) prior to being processed by the pre-processingcircuits 965 a-n.

Control Circuitry

The control circuitry 939 may be any combination of hardware gate logicand/or a processor executing a code stored in a volatile or non-volatilememory. The control circuitry 939 interfaces with the image capturecontrol and decode system 107, the pre-processing circuits 965 a-n, andthe photo sensor array 102.

In operation the control circuitry may receive, from the image capturecontrol and decode system 107 via bus 200, image capture parametervalues for a burst of one or more image frames (full, binned,sub-sampled, and/or cropped) to be sequentially captured. As will bedescribed in more detail herein, the image capture parameter valuesdefine, for the burst of one or more image frames to be captured by thephoto sensor, a quantity of image frames to be sequentially captured(the burst of images) and, for each image within the burst: i) whether afull image frame, binned image frame, sub-sampled image frame, or awindow of a full, binned, or sub-sampled image frame is to be captured;ii) the binning or subsampling resolution (vertically and horizontally)and/or window cropping, if applicable; iii) an exposure setting; iv) again setting; and v) an indication of a permutation of one or morepre-processing functions to apply to the image frame (full, binned,sub-sampled and/or windowed), including pre-processing functions thatare to be applied to an image data record resulting from a previouspre-processing function being applied to the image frame (full, binned,sub-sampled, and/or windowed).

In further operation, after receiving the image capture parametervalues, the control circuitry 939 may, for each image frame to becaptured, set image capture settings to the image capture parametervalues for the image frame and, in response to a trigger signal from theimage capture system package 107, drive the photo sensor array 102 tosequentially capture each of one or more image frames of the burst inaccordance with the image capture settings and without further triggersignal(s) from the image capture control and decode system 107.

In more detail, the control circuitry 939 adjusts the image capturesettings between the exposure periods for each sequentially capturedimage frame such that each captured image frame within the burst ofimage frames is captured with image capture settings specificallydefined for that image frame by the image capture control and decodesystem 107. At least one of the multiple frames of image data may becaptured with a distinct value of at least one image capture parameter.

Each captured image frame (full, binned, sub-sampled, and/or windowed)may, under control of the control circuitry 939 be input to selected oneor more pre-processing circuits 965 a-n in accordance with the imagecapture parameter values for purposes of performing the pre-processingfunctions previously described. Resulting image data records 967 a-n arewritten to the image buffer 963.

Further, the control circuitry 939 may, for selected image data records967 a-n in the buffer memory 963, drive selected other pre-processingcircuits 965 a-n to receive the selected image data record 967 a-n andgenerate, and write to the image buffer 963, an image data record 967a-n which is derived therefrom.

Further yet, the control circuitry 939 may, as requested by the imagecapture control and decode system 107, provide certain image datarecords 967 a-n (or portions of certain image data records 967 a-n) tothe image capture control and decode system 107 for further processingand decode.

Image Capture and Decode Module

In one embodiment, the image capture module 962 of the image capturecontrol and decode system 107, when executed by the processor 948 inconjunction with the hardware circuits 950, controls image capture by:i) defining (or receiving from the decoder 980) image capture parametervalues for a burst of one or more image frames to be sequentiallycaptured by the photo sensor array 102 of the image sensor package 111and the image processing to be performed on each image frame; ii)initiating the capture of the sequence of one or more image frames bythe photo sensor array 102 and the corresponding performance of theimage processing thereon by the pre-processing circuits 965 a-n togenerate image data records 967 a-n, each of which is a derivative of animage frame within the sequence of one or more image frames; and iii)controlling the illumination systems 930 a-c to illuminate the barcodewithin the field of view during capture of each frame of the sequence ofone or more image frames. The image capture module 962 may furtherdefine, or receive from the decoder an indication of, which of the imagedata records, or portions of the image data records are to be providedto the decoder 980 for decoding of the barcode.

As described, the image capture parameter values may define a quantityof image frames to be sequentially captured (the burst of images) and,for each image within the burst: i) whether a full image frame, binnedimage frame, sub-sampled image frame, or a window of a full, binned, orsubsampled image frame is to be captured; ii) the binning or subsamplingresolution (vertically and horizontally) and/or the windowing croppingfor the image frame to be captured if applicable; iii) an exposuresetting; iv) a gain setting, v) an indication of a permutation of one ormore previously described pre-processing functions to apply to the imageframe (full, binned, sub-sampled, and/or cropped) by the imagepre-processing circuits 965 a-n within hardware circuits 941 of theimage sensor system package 111, including pre-processing functions thatare to be applied to an image data records 967 a-n resulting from aprevious pre-processing function being applied to the image frame (full,binned, sub-sampled and/or cropped).

The exposure period may be the duration of time each pixel is exposed(i.e., the duration of time between the beginning of the exposure periodand the end of the exposure period).

The gain setting may be a gain value implemented for ensuring that thepixel intensity values (or binned pixel intensity values) utilize thedynamic range of the A/D converters.

Initiating the capture of the sequence of one or more image frames of abarcode within a field of view of the photo sensor array 102 may includeproviding a single trigger signal to the control circuitry 939 of theimage sensor system package 111 to initiate the capture of the sequenceof one or more image frames. Such single trigger signal may be providedafter the image capture parameter values defining the sequence of imageframes to be captured and pre-processing to be performed bypre-processing circuits 965 a-n within the image sensor system package111 have been provided to the control circuitry 939 such that thecontrol circuitry 939 may autonomously capture the sequence of imageframes and drive the pre-processing circuits 965 a-n to perform theapplicable pre-processing in accordance with the image capture parametervalues without further control having to be provided by the imagecapture control and decode system 107.

Controlling the illumination systems 930 a-c to illuminate the barcodewithin the field of view during capture of each frame of the sequence ofone or more image frames may comprise controlling illumination logic 954within hardware circuits 950.

In more detail, the illumination sub-systems 930 a-c are coupled to thehardware circuits 950 which providing power required for the lightemitting diodes (LEDs) or other illumination sources to generateillumination under control of illumination logic 954. More specifically,for each image frame to be captured by the photo sensor array 102, theimage capture module 962 provides illumination parameters to theillumination logic 954 which control the illumination settings to beused for capture of the image frame. More specifically, the illuminationparameters may define such illumination settings as: i) identifyingwhich of at least one of the illumination sub-systems 930 a-c are to beactivated for the exposure period in which the image frame is captured;and ii) the intensity of illumination to be generated by each of theillumination sub-systems 930 a-c that are to be activated. In certainexemplary embodiments the intensity may be defined as: i) a percentagefrom zero percent (0%) to one hundred percent (100%) representing thepercent of a maximum illumination intensity that can be generated by theLEDs (or other illumination sources) of illumination sub-system; ii)pulse-width-modulation (PWM) parameters representing the percentage oftime during the exposure period that maximum operating power is appliedto the LEDs (or other illumination sources) of the illuminationsub-system in a pulsing pattern; and iii) a percentage greater than onehundred percent (100%) representing a power level to be applied if theLEDs of illumination sub-system if the LEDs are to be over-driven.

In certain embodiments, the illumination parameters may be provided tothe illumination logic 954 for one or more image frames within a burstof image frames to be captured by the photo sensor array 102 by theimage capture module 962 writing the illumination parameters for eachframe to a distinct register within the illumination logic 954.

During capture of each image frame of one or more image frames within aburst of image frames, the illumination logic 954 sets the illuminationsettings for the image frame to conform to the illumination parametersfor the image frame by configuring power circuits of the hardwarecircuits 950 to apply the applicable power to the applicableillumination sub-systems.

In one embodiment, the illumination logic is coupled to a flash signal206 generated by the control module 939 of the image sensor systempackage 111. The flash signal is configured to generate a signalindicating a start of each exposure period and an end of each exposureperiod, for each image frame captured by the image sensor 102 within aburst of one or more image frames. In this embodiment the illuminationlogic may, for each image frame: i) set the illumination settings forthe image frame to conform to the illumination parameters for the imageframe by configuring power circuits of the hardware circuits 950 toapply the applicable power to the applicable illumination sub-systems;ii) apply the applicable power to the applicable illumination sub-system930 a-c when the flash signal 206 indicates start of the exposure periodfor the image frame; ii) deactivate the power to the illuminationsub-systems 930 a-c) when the flash signal 206 indicates the end of theexposure period; and iv) repeat steps i-iii for the next image framewithin the sequence utilizing the illumination parameters for that nextimage frame within the sequence. The illumination parameters may beconsidered image capture parameter values in addition to those imagecapture parameter values previously described.

Decoder

The Decoder 980, when executed by the processor 948, may: i) determinewhich of the one or more image data records 967 a-n (or windows withinone or more image data records 967 a-n) may be transferred from theimage buffer 963 to the image capture control and decode system 107; ii)determine a permutation of one or more pre-processing functions(performed by pre-processing circuits 951 a-n) to apply to each of theone of the image data records 967 a-n (or windows within one or moreimage data records 967 a-n) to generate, and write to the buffer memory970, image data records 953 a-n (each of which is also a derivative ofthe one or more image frames (whether full, binned, or sub-sampled)captured by the photo sensor array 102; iii) determine a permutation ofone or more pre-processing functions (performed by the image processingmodule 979 when such code is executed by the processor 948) to apply toeach of the one of the image data records 953 a-n (or windows within oneor more image data records 953 a-n) to generate, and write to the buffermemory 970, additional (or replacement) image data records 953 a-n (eachof which is also a derivative of the one or more image frames (full,binned, sub-sampled, and/or cropped) captured by the photo sensor array102; and iv) decode the barcode present within the field of view of thebarcode reader and imaged within the one or more image frames (whetherfull, binned, or sub-sampled) captured by the photo sensor array 102 andrepresented by at least a portion of one of the image data records 953a-n derived from such image frame.

Referring to FIG. 11, exemplary operation of the decoder is depicted inaccordance with one embodiment. Step 1102 represents the decoder 980and/or the image capture module 962 determining the image captureparameter values for a burst of one or more image frames as previouslydescribed.

Step 1104 represents transferring one or more image data records 967 a-n(or portions of one or more image data records 967 a-n) from the imagebuffer 963 to the image capture control and decode system 107 andestablishing which, if any, pre-processing functions are to be performedby image pre-processing circuits 951 a-n and/or the image processingmodule 979.

Step 1106 represents selecting an image data record 953 for decoding,which may include sampling final image data records 953 a-n at step 1106a and evaluating the sample image data records 953 a-n at step 1106 b.

Step 1108 represents decoding the selected image data record 953. Thisoperation may include, based on the resulting image data records 953 a-nmeeting or failing to meet certain criteria: i) driving imagepre-processing circuits 951 a-n or the processing module 979 to performadditional image processing operations, as previously described on oneor more of the image data records 953 a-n within the buffer memory 970(or on a window of, a binning of, or a sub-sampling of each of one ormore image data records 953 a-n) and write resulting additional, orreplacement, image data records 953 a-n to the buffer memory 970; ii)driving the transfer of one or more additional image data records 967a-n (full, windowed, binned, or sub-sampled) to the image capturecontrol and decode system 107 (without obtaining an additional burst ofone or more image frames) and, optionally driving performance ofadditional pre-processing operations on the additional image datarecords 967 a-n by the pre-processing circuits 951 a-n or the imageprocessing module 979; and/or iii) driving capture of one or moreadditional bursts of image frames (whether full, windowed, binned orsub-sampled), resulting in one or more additional image data records 967a-n being written to the image buffer 963, and then driving transfer ofone or more of the additional image data records 967 a-n (full,windowed, binned or sub-sampled), but not necessarily all of theadditional image data records 967 a-n in the image buffer 963, to theimage capture control and decode system 107 and, optionally drivingperformance of additional pre-processing operations on the additionalimage data records 967 a-n by the pre-processing circuits 951 a-n or theimage processing module 9797. This aspect of the operation may berepeated until at least one of the image data records 953 a-n isdecodable by the processor 948 operating the decoder 980.

Pre-Processing Circuits 951

The pre-processing circuits 951 a-n, similar to pre-processing circuits965 a-n may be implemented within hardware gate logic 950. Thepre-processing circuits 951 a-n may perform operations such asconvolution, binning, sub-sampling and other image processing functionson image data records 967 a-n (each of which is provided by the imagesensor system package 107 via the bus 200 and each of which is, or is aderivative of, an image frame (full, binned, sub-sampled, and/orcropped) captured by the photo sensor array 102) to generate, and writeto the buffer memory 970, one or more image data record 953 a-n.

Each pre-processing circuit 951 a-n may receive as input either: i) animage data record 967 a-n (or a window of, a binning of, or asub-sampling of, an image data record 967 a-n) directly from the imagesensor system package 111 by way of the wide bus 200; or ii) an imagedata record 953 a-n from the buffer memory 970 which is the result of adifferent pre-processing circuit 951 a-n previously operating on animage data record 967 a-n (or a window of, a binning of, or asub-sampling of, an image data record 967 a-n) received from the imagesensor system package 111 by way of the wide bus 200.

It should be noted that one image data record 967 a-n (or a window of, abinning of, or a sub-sampling of, an image data record 967 a-n) may beinput to multiple pre-processing circuits 951 a-n, resulting in multipleimage data records 953 a-n being written to the buffer memory 970 forthe same image data record 967 a-n (or a window of, a binning of, or asub-sampling of, an image data record 967 a-n).

Further, for a burst of multiple image frames the image data record 967a-n (or a window of, a binning of, or a sub-sampling of, an image datarecord 967 a-n) received and processed by the pre-processing circuits951 a-n may represent different image frames within the burst capturedby the photo sensor array 102. The image data records 967 a-n (or awindow of, a binning of, or a sub-sampling of, an image data record 967a-n) received and processed by the pre-processing circuits 951 a-n maybe the result of applying the same pre-processing functions bypre-processing circuits 965 a-n to each of multiple image frames withinthe burst.

Each image data record 967 a-n (or a window of, a binning of, or asub-sampling of, an image data record 967 a-n) received may be input tothe same one or more pre-processing circuits 951 a-n or may be input todifferent subsets of pre-processing circuits 951 a-n, each subsetincluding one or more pre-processing circuits 951 a-n.

It should also be noted that one of the pre-processing circuits 951 a-nmay simply write the image data record 967 a-n (which may be an imageframe captured by the image sensor array 102 (full, binned, sub-sampled,and/or cropped) without previous processing by pre-processing circuits965 a-n) to the buffer memory 970 without performing substantive imageprocessing.

Referring again to FIG. 14, operations performed by, and derivatives ofthe frame of image data produced by, the pre-processing circuits 951 a-nmay include: i) transfer of the image data record 967 a-n (or a window,binning, or sub-sampling of the image data record 967 a-n) to the buffermemory 970 as an image data record 953 a-n without substantiveprocessing; ii) binning of an image data record 967 a-n (or a window orsub-sampling of the image data record 967 a-n) and writing the result tothe buffer memory 970 as an image data record 953 a-n; iii) subsamplingof an image data record 967 a-n (or a window, binning, or sub-samplingof the image data record 967 a-n) and writing the result to the buffermemory 970 as an image data record 953 a-n; iv) generating a rotation ofan image data record 967 a-n (or a window of, a binning of, orsub-sampling of the image data record 967 a-n) and writing the result tothe buffer memory 970 as an image data record 953 a-n; v) generating aconvolution of an image data record 967 a-n (or a window or sub-samplingof the image data record 967 a-n) and writing the result to the buffermemory 970 as an image data record 953 a-n; and vi); generating a doubleconvolution, which is a second sequential convolution performed on theresult of a previously performed convolution, of an image data record967 a-n (or a window or sub-sampling of the image data record 967 a-n)and writing the result to the buffer memory 970 as an image data record953 a-n. Each sequential convolution utilizes a different distinctkernel.

The pre-processing circuits 951 a-n may be implemented in hardware gatelogic 950 to provide for image processing very quickly such thatprocessing by a pre-processing circuit 951 a-n, and thereby generating,and storing in the buffer memory 970, one or more image data records 953a-n may be performed during the limited amount of time that the imagedata records 967 a-n are being transferred to the image capture controland decode system 107 via the bus 200 without requiring storage of thetransferred image data records 967 a-n in memory prior to pre-processingby pre-processing circuits 951 a-n.

Image Processing Module

The image processing module 979, when executed by the processor 948 mayperform similar pre-processing functions as performed by thepre-processing circuits 965 a-n and pre-processing circuits 951 a-n.

In more detail, the image processing module 979 may perform operationssuch as convolution, binning, sub-sampling and other image processingfunctions on image data records 953 a-n (each of which is has beenpreviously written to the buffer memory 970 and each of which is, or isa derivative of, an image frame (full, binned, sub-sampled, and/orcropped) captured by the photo sensor array 102) to generate, and writeto the buffer memory 970, one or more additional, or replacement, imagedata record 953 a-n.

The image processing module 979 may receive as input an image datarecord 953 a-n (or a window of, a binning of, or a sub-sampling of, animage data record 953 a-n) from the buffer memory 970.

It should be noted that one image data record 953 a-n (or a window of, abinning of, or a sub-sampling of, an image data record 953 a-n) may beinput to multiple pre-processing functions of the image processingmodule 979 resulting in multiple additional, or replacement, image datarecords 953 a-n being written to the buffer memory 970 for the sameimage data record 953 a-n (or a window of, a binning of, or asub-sampling of, an image data record 953 a-n).

Further, for a burst of multiple image frames, the image data record 953a-n (or a window of, a binning of, or a sub-sampling of, an image datarecord 953 a-n) received and processed by the image processing module979 may represent different image frames within the burst captured bythe photo sensor array 102. The image data records 953 a-n (or a windowof, a binning of, or a sub-sampling of, an image data record 943 a-n)received and processed by the image processing module 979 may be theresult of applying the same pre-processing functions to each of multipleimage frames within the burst.

Each image data record 953 a-n (or a window of, a binning of, or asub-sampling of, an image data record 953 a-n) may be input to the sameone or more pre-processing functions of the image processing module 979or may be input to different subsets of pre-processing functions ofimage processing module 979, each subset including one or morepre-processing functions.

Referring again to FIG. 14, operations performed by, and derivatives ofthe frame of image data produced by, the image processing module 979 mayinclude: i) binning of an image data record 953 a-n (or a window orsub-sampling of the image data record 953 a-n) and writing the result tothe buffer memory 970 as an additional, or replacement, image datarecord 953 a-n; ii) subsampling of an image data record 951 a-n (or awindow, binning, or sub-sampling of the image data record 951 a-n) andwriting the result to the buffer memory 970 as an additional, orreplacement, image data record 953 a-n; iii) generating a rotation of animage data record 953 a-n (or a window of, a binning of, or sub-samplingof the image data record 953 a-n) and writing the result to the buffermemory 970 as an additional, or replacement, image data record 953 a-n;iv) generating a convolution of an image data record 953 a-n (or awindow or sub-sampling of the image data record 953 a-n) and writing theresult to the buffer memory 970 as an additional, or replacement, imagedata record 953 a-n; and v); generating a double convolution, which is asecond sequential convolution performed on the result of a previouslyperformed convolution, of an image data record 953 a-n (or a window orsub-sampling of the image data record 953 a-n) and writing the result tothe buffer memory 970 as an additional, or replacement, image datarecord 953 a-n. Again, each sequential convolution utilizes a differentdistinct kernel.

Further, as previously discussed, the decoder may additionally, prior tothe capture of the burst one or more image frames by the photo sensorarray 102, based on analysis of image data records 953 a-n derived fromone or more previous bursts of one or more image frames (full, binned,sub-sampled, and/or cropped) define any permutation of, or all of, theimage capture parameter values previously discussed for the burst (ornext burst) of one or more image frames.

Again, such image capture parameter values defining: a quantity of imageframes to be sequentially captured (the burst of images) and, for eachimage within the burst: i) whether a full image frame, binned imageframe, or sub-sampled image frame is to be captured; ii) the binning orsubsampling resolution (vertically and horizontally) for the image frameto be captured if applicable; iii) an exposure setting; iv) a gainsetting, v) an indication of a permutation of one or more pre-processingfunctions to apply to the image frame (full, binned, or sub-sampled),including pre-processing functions that are to be applied to an imagedata record resulting from a previous pre-processing function beingapplied to the image frame (whether full, binned, or sub-sampled).

The image capture parameter values may be provided directly by thedecoder 980 to the control circuitry 939 of the image capture systempackage 111 via the bus 200 or may be provided to the image capturemodule 962 which in turn provides the image capture parameter values tothe control circuitry 939 of the image capture system package 111 viathe bus 200.

Interface 200

As discussed, the image sensor system package 111 and the image capturecontrol and decode system 107 may be included in two separate packagescommunicating over the interface 200.

FIG. 9D shows the interface 200 between the image sensor system package111 and the image capture control and decode system 107. The interface200 may comprise a control link 202 that may be a two-way serial controlchannel enabling the image capture control and decode system 107 to: i)set parameters (e.g., the quantity of images to be captured in a burst,exposure period for each frame, gain setting for each frame, resolutionsetting for each frame, or the like); ii) select which imagepre-processing circuits 965 a-n are to be applied to each capturedframe, thereby determining the characteristics of the image data records967 a-n written to the image buffer 963; and iii) select image datarecords 967 for transfer to the image capture control and decode system107.

The interface 200 may further include a trigger signal line 204controlled by the image capture control and decode system 107 toinitiate autonomous capture of a burst of one or more image frames andsubsequent image pre-processing and writing of image data records 967a-n to the image buffer 963.

The interface 200 may further include a flash signal line 206 which isoutput by the image sensor system package 111 to signal the start ofeach exposure period and the end of each exposure period. The imagecapture control and decode system 107 may control the illuminationsystem 103 based on the flash signal on the flash signal line 206. Moreparticularly, the image capture control and decode system 107 mayactivate the selected illumination system(s) 930 a-n at the selectedintensities during the exposure of each applicable frame based on theflash signal line 206 indicating start of the exposure period. Theillumination system 103 may be configured to deactivate the exposureillumination when the flash signal line 206 indicates end of theexposure period activate the targeting illumination during the timeperiod between exposure periods of sequential frames.

The interface 200 may further include data lines 208 that may beparallel or serial and that provide for the transfer of image datarecords 967 from the image sensor system package 111 to the imagecapture control and decode system 107.

The interface 200 may further include data control signals 210 which maybe signals to indicate the time each pixel value is valid on a dataline, and indicate location of the pixel within the image arrayrepresented by the image data records (e.g., horizontal blanking,vertical blanking).

It should be appreciated that the barcode image is captured, processed,and stored in the first package (i.e., the image sensor system package111) at a much faster speed and may then be transferred to the secondpackage (the image capture control and decode system 107) for decodingat a slower speed. The image buffer 963 may be large enough to hold anentire frame of image data (in combination with image data records 967a-n derived from the frame of image data), and the entire frame of imagedata and/or combinations of one or more image data records 967 a-n maybe read-out of the image buffer 963 after the entire frame of image datais put into the image buffer 963.

In one embodiment, instead of transferring all frames of image datacaptured in a burst, a subset of the multiple frames of image datagenerated in a burst may be transferred to the image capture control anddecode system 107 at a speed commensurate with transfer by bus 200 thesecond or slower speed).

Operation

Referring to FIG. 10 in conjunction with FIGS. 9A-9C, an exemplaryoperation of certain components of the barcode reader 10 are representedin accordance with an embodiment of the present invention.

Step 1002 represents defining image capture parameter values for a burstof image frames to capture. In more detail, defining the image captureparameter values may comprise the image capture module 962 or thedecoder module 980 defining the quantity of image frames to capture(full, binned, sub-sampled, and/or windowed) in sequence at sub-step1004 and for each frame in the sequence, defining: i) image captureparameter values for the image frame such as the exposure period, gainsettings, and/or resolution settings (if capturing a binned orsub-sampled image frame) at sub-step 1006 a; ii) the image processingfunctions to which the image frame will be subject by pre-processingcircuits 965 a-n for purposes of defining the image data records 967 a-nto be written to the image buffer 963 at sub-step 1006 b; and/or iii)the illumination settings for the image frame at sub-step 1006 c.

The illumination settings may be defined as a combination of: i)identifying which illumination sub-systems 930 a-c are to be used forcapturing the image frame and ii) for each illumination sub-system 930a-c, the percentage of full intensity at which the illumination is to beactivated.

More specifically, the status of each illumination sub-system 930 a, 930b, 930 c (i.e., active or non-active and, if active, the intensitylevel) may be different for each image frame captured. For example, whentwo sequential frames are captured, the first frame may be captured withonly illumination sub-system 930 a active while the second frame may becaptured with only illumination sub-system 930 b active.

Further, the selection of image capture parameter values, including thenon-active and active illumination sub-systems 930 a, 930 b, 930 c forcapturing images, may be based on characteristics of the image datarecords 967 a-n in the image buffer 963 or image data records 953 a-n inthe buffer memory 970 from previously captured image frames.

Step 1008 represents: i) transferring the image capture parameter valuesfor the image capture burst to the control circuitry 939 of the imagesensor system package 111 utilizing the bi-directional control link 202of the interface 200; and ii) configuring the illumination logic todrive the applicable illumination sub-system 930 a-c in accordance withthe illumination parameters during an exposure time for capture of eachimage frame. It should be appreciated that image capture parametervalues transferred to the control circuitry 939 do not need to includeparameter values related to illumination when illumination is controlledby hardware logic 954 within the image capture system package 107.However, in an embodiment wherein the illumination logic 954 controllingillumination sub-systems 930 a-n is within the image sensor systempackage 111 (not shown on FIG. 9a ) then illumination parameter valueswould be transferred to the control circuitry 939.

Step 1010 represents driving the single trigger signal to the controlcircuitry 939 to initiate capture of the burst of one or more imageframes, and subsequent image pre-processing and writing of image datarecords 967 a-n to the image buffer 963 which, as discussed may bewithout further control by the image capture system package 107.

Step 1012 represents the illumination logic 954 receiving from thecontrol circuitry 939 of the image sensor system package 111, for eachimage frame of the burst, a flash signal 1012 a-c indicative of theexposure period commencement and termination for the image frame andactivating the illumination system 103 in accordance with theillumination settings applicable to that image frame as defined at step1006 c.

Step 1014 represents activating targeting illumination after capturingthe burst of image frames for purposes of projecting a targeting patternof illumination into the field of view to assist the operator of thebarcode reader in maintaining the desired barcode within the field ofview 106 of the barcode reader in case an additional burst of one ormore image frames is required. After the barcode within the field ofview 106 has been decoded the targeting illumination may be deactivated.

Step 1016 represents selecting which image data records 967 a-n (orselected portions or windows within each image data record 967 a-n) areto be transferred from the image buffer 963 to the image capture controland decode system 107. More specifically, the decoder 980 or the imagecapture module 962 may obtain portions (e.g., samples) of one or moreimage data records 967 a-n at sub-step 1016 a and evaluate each for thequality of the image of the barcode within the image data record atsub-step 1016 b to select one or more image data records 967 a-n, butfewer than all image data records 967 a-n, to transfer from the imagebuffer 963 to the image capture control and decode system 107 fordecoding.

The image data records 967 a-n being transferred may have the bestquality image of the barcode or other characteristics of the image ofthe barcode which are likely to result in a decodable barcode image. Forexample, the quality of an image of a barcode may be measured in termsof the contrast between light cells and dark cells within the barcode. Abarcode image having relatively high contrast between dark cells andlight cells may be considered to have higher quality than a barcodeimage having relatively low contrast between dark cells and light cells.

The superior contrast profile may mean at least one of: (i) greatermaximum amplitude between the portions of the image within the subsetthat are dark marks of the barcode and the portions of the image withinthe subset that are light marks of the barcode; and (ii) more distincttransitions between portions of the image within the subset that aredark marks of the barcode and the portions of the image within thesubset that are light marks of the barcode.

The terms “dark cells” and “light cells” are used herein becausebarcodes have traditionally been printed with ink. This gives barcodesthe appearance of having dark cells (the portion that is printed withink) and light cells (the unprinted substrate background, typicallywhite). However, with direct part mark technology, ink is not alwaysused and other techniques (e.g., laser/chemical etching and/or dotpeening) may be used instead. Such techniques may be utilized to createa barcode by causing different portions of a substrate to have differentreflective characteristics. When these different portions of thesubstrate are imaged, the resulting barcode image may have theappearance of including dark cells and light cells. Therefore, as usedherein, the terms “dark cells” and “light cells” should be interpretedas applying to barcodes that are printed with ink as well as barcodesthat are created using other technologies.

The contrast between the dark cells and the light cells in a barcode maybe a function of illumination. Ideally, it is desirable to provideillumination that is consistent across the barcode and of intensity suchthat the exposure of the image yields both dark cells and light cellsthat are within the dynamic range of the photo sensor array 102. Thisyields better contrast than any of the following: (i) a dimly litbarcode; (ii) a brightly lit barcode wherein the image is washed outbeyond the dynamic range of the photo sensor array 102; (iii) anunevenly lit barcode with bright washed out spots; or (iv) a barcodeilluminated with illumination that is not compatible with thereflectivity characteristic(s) of the cells of the barcode. An exampleof (iv) is that illumination directed from the sides of the field ofview yields a higher contrast image of a barcode formed by etchingtechnology than does illumination parallel to the optical axis.

If the quality of a window of images is measured in terms of contrast,determining the selected illumination system configuration may includedetermining which window image of the plurality of window images has thehighest contrast between light and dark cells of the barcode, anddetermining which configuration of the plurality of illumination systems930 a-c was activated when the window image having the highest contrastwas captured.

In one embodiment, each of the image data records 967 a-n which aretransferred to the image capture control and decode system 107 may bewritten to the image buffer 970 as image data records 953 a-n withoutfurther image processing. In another embodiment, the imagepre-processing circuits 951 a-n may perform image processing and writingof resulting image data records 953 a-n to the buffer memory 970 aspreviously discussed.

Also, as previously discussed, one of the pre-processing circuits 965a-n may simply write input data as an image data record 967 a-n to theimage buffer 963 without additional substantive processing.

As such, the structure depicted in FIG. 9A and FIG. 9B enables an imageframe, as captured by the photo sensor array 102, to be written as animage data record 967 to image buffer 963 without substantive processingthen subsequently transferred to the image capture control and decodesystem 107 where it either: i) undergoes image pre-processing by one ormore pre-processing circuits 951 a-n, resulting in one or more imagedata records 953 a-n being written to the image buffer 970 as a resultof such pre-processing; or ii) is written to the image buffer 970 as animage data record 953 a-n without pre-processing by either thepre-processing circuits 965 a-n or the pre-processing circuits 951 a-n.

The structure depicted in FIG. 9A and FIG. 9B also enables an imageframe, as captured by the photo sensor array 102, to undergo imagepre-processing utilizing one or more pre-processing circuits 965 a-n andto be written to the image buffer 963 as one or more image data records967 a-n and then have one or more of the image data records 967 a-ntransferred to the image capture control and decode system 107 where thetransferred image data records 967 a-n are: i) written to the imagebuffer 970 as image data records 953 a-n without further pre-processing;or ii) subjected to further pre-processing by image pre-processingcircuits 951 a-n, resulting in writing of image data records 953 a-n tothe image buffer 970.

Further, as discussed, processing module 979 may undertake processing ofone or more image data records 953 a-n to modify the image data recordsand/or generate additional, or replacement, image data records from oneor more image data records 953 a-n. As such, any image data record 953a-n may be processed by the image processing module 979 prior to beingsubjected to decoding, whether it is: i) representative of the imageframe captured by the photo sensor array 102 without substantiveprocessing by either the pre-processing circuits 965 a-n or thepre-processing circuits 951 a-n; ii) pre-processed by one of thepre-processing circuits 965 a-n but without further substantivepre-processing by one of the pre-processing circuits 951 a-n; iii) notsubstantively processed by one of the pre-processing circuits 965 a-nbut substantively pre-processed by one of the pre-processing circuits951 a-n; or iv) substantively pre-processed by both one of thepre-processing circuits 965 a-n and one of the pre-processing circuits951 a-n.

Preprocessing

Examples of pre-processing will be explained hereafter. The followingexamples of pre-processing may be: i) performed by the pre-processingcircuits 965 a-n on a frame of image data received from the photo sensorarray 102 to generate image data records 967 a-n, which are the imageframe or a derivative of the image frame, to be written to the imagebuffer 963; ii) performed by the pre-processing circuits 951 a-n and/orthe image processing module 979 (executed by the processor 948) on animage data record 967 a-n transferred from the image buffer 963 to theimage capture control and decode system 107 for generating an image datarecord 953 a-n which may be the original image frame or a derivative ofthe original image frame.

Preprocessing Example A

In one embodiment, no image processing may be performed such that theimage data record may be the image frame (whether full, windowed,binned, or sub-sampled) without substantive processing.

Preprocessing Example B

In another embodiment, portions of the image frame may be croppedhorizontally or vertically such that the image data record may be awindowed portion of the image frame (whether full, binned orsub-sampled).

Preprocessing Example C

In another embodiment, the image data record may be a lower resolutionframe of the original image data. One of the pre-processing circuits maybin, or average, two or more pixel intensity values to generate a singleintensity value representative of a theoretical pixel that encompassesthe size of all of the pixels that provided values that were binned oraveraged. Multiple image data records can be generated from the sameframe of image data at different resolutions. Referring to FIG. 12A: i)220 represents binning four pixels (e.g., averaging the four intensityvalues) to reduce the resolution to 25% of the resolution of the inputimage; ii) 222 represents vertical binning of two pixels to reducevertical resolution by 50% without affecting horizontal resolution; andiii) 224 represents horizontal binning of two pixels to reducehorizontal resolution by 50% without affecting vertical resolution. Itshould be noted that FIG. 12A shows examples only and the binning mayinclude any other grouping of pixels for resolution reduction.

Preprocessing Example D

In another embodiment, binarization may be performed. The binarizationmay involve comparing the intensity value of each pixel, or theintensity value resulting from the binning of a group of pixels, to athreshold. If it is greater than (or equal to) the threshold, theintensity value may be converted to a first binary value, and if it isless than (or equal to) the threshold, the intensity value may beconverted to a second binary value. The threshold may be common acrossall pixels (or binned pixel groupings) or may be different for differentpixels (or binned pixel groupings). The threshold value applied to anypixel (or binned pixel groupings) may be dynamic (e.g., the thresholdvalue may be calculated based on the intensity values previouslyoperated on during the binarization process).

Preprocessing Example E

In another embodiment, a minimum/maximum processing technique may beapplied to any array of pixel intensity values or any array of binned orsubsampled array of intensity values. It may be applied across theentire frame of image data (or an image data record) or to only acropped section of the frame of image data (or an image data record).Referring to FIG. 12B, an exemplary 3×3 kernel 230 encompasses 9 pixelintensity values (or 9 binned intensity values). Of those 9 intensityvalues, the maximum intensity value or the minimum intensity value isdetermined and written to the image data record in substitution for theintensity value of the center value 234 for kernel 230. The kernel isthen shifted to the next center value 236 (represented by kernel 232,which is shown shifted up slightly for clarity) and the maximum orminimum value among the nine intensity values is calculated forreplacement of intensity value 236.

Preprocessing Example F

In another embodiment, convolution kernel masking may be performed. Inthis image processing technique, a kernel mask, such as the 3×3 kernelmask 240 as shown in FIG. 12C as an example, may be applied to a 3×3group of pixel intensity values (or a 3×3 group of binned intensityvalues) to determine an intensity value to replace the center intensityvalue. More specifically, each intensity value is multiplied by the maskvalue (in the example of FIG. 12C, the center intensity value ismultiplied by 8 and each surrounding intensity value is multiplied by−1) and then the resulting 9 values are averaged to determine theintensity value to replace the center intensity value. The kernel isthen shifted by one pixel as described with respect to FIG. 12B todetermine the intensity value for the next pixel.

Preprocessing Example G

In another embodiment, a rotation may be performed as shown in FIG. 12Don an array of pixel values. More specifically, each intensity value forselected columns of the array (e.g. 3, 5, 7) may be extracted and usedfor intensity values of adjacent rows within an image data record. Theselected columns may be adjacent columns or may be a fraction of thecolumns, evenly spaced, across all or a portion of the array. The arraymay be the image data (full, binned, sub-sampled, and/or windowed).

It should be appreciated that using one or more of the above processingtechniques, image data records can be generated from the original imageframe or image data records that have already been generated from theoriginal image frame. Multiple processing techniques may be applied tothe same frame of image data (or image data record) to result indifferent image data records derived therefrom, and the processingtechniques may be applied in any order.

Sets of image data records may be generated from one or more imageframes captured in a single sequence or in multiple sequences, and maybe generated by a combination of the pre-processing circuits 965 a-n ofthe image sensor system package 111, pre-processing circuits 951 a-n ofthe image capture control and decode system 107, and/or the processor148 of the image capture control and decode system 107 executing theimage processing module 979. For example, an image data record may be aframe of image data which may be an array of pixel intensity values,each pixel intensity value representing the intensity of illuminationaccumulating on the photo sensor pixel over the exposure period.Different image data records may each be a frame of image data capturedusing a different exposure period as shown in FIG. 13A, using adifferent gain setting, or using a different exposure illuminationactive during a different exposure period as shown in FIG. 13B. FIG. 13Ashows, as an example, three image frames generated by using differentexposure settings, respectively. FIG. 13B shows, as an example, fourimage frames that are generated using different illumination systems anddifferent exposure settings. Only one of the illumination systems 930 a,930 b, 930 c may be active during the exposure period for a first imagedata record while a different one of the illumination systems 930 a, 930b, 930 c may be active during the exposure period for a second imagedata record.

Further, although not shown in FIG. 13B, multiple illumination systemsmay be active for an exposure period, at intensities that may bedifferent. For example, during a first exposure period a firstillumination system 930 a may be active at 10% power and a secondillumination system 930 b may be active at 60% power and, during asecond exposure period the first illumination system may be active at30% power while the second illumination system may be active at 20%power.

As used herein, the phrase “substantially parallel” means within fivedegrees of parallel. In another embodiment, substantially parallel meanswithin 15 degrees of parallel. In another embodiment, substantiallyparallel means within 20 degrees of parallel.

As used herein, the phrase “substantially perpendicular” means withinfive degrees of perpendicular. In another embodiment, substantiallyperpendicular means within 15 degrees of perpendicular. In anotherembodiment, substantially perpendicular means within 20 degrees ofperpendicular.

As used herein, the term “determining” encompasses a wide variety ofactions and, therefore, “determining” can include calculating,computing, processing, deriving, investigating, looking up (e.g.,looking up in a table, a database or another data structure),ascertaining and the like. Also, “determining” can include receiving(e.g., receiving information), accessing (e.g., accessing data in amemory) and the like. Also, “determining” can include resolving,selecting, choosing, establishing and the like.

As used herein, the phrase “based on” does not mean “based only on,”unless expressly specified otherwise. In other words, the phrase “basedon” describes both “based only on” and “based at least on.”

One or more of the features, functions, procedures, operations,components, elements, structures, etc., described in connection with anyone of the configurations described herein may be combined with one ormore of the functions, procedures, operations, components, elements,structures, etc., described in connection with any of the otherconfigurations described herein, where compatible.

The steps and/or actions of the methods described herein may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isrequired for proper operation of the method that is being described, theorder and/or use of specific steps and/or actions may be modifiedwithout departing from the scope of the claims.

The claims are not limited to the specific implementations describedabove. Various modifications, changes and variations may be made in thearrangement, operation and details of the implementations describedherein without departing from the scope of the claims.

What is claimed is:
 1. A barcode reader, comprising: an array ofphotosensors organized in a grid of pixels including photosensitiveregions for capturing image data, the grid of pixels defined by multiplerows of pixels and multiple columns of pixels, each row of pixelsincluding a first plurality of pixels, wherein each pixel of the firstplurality of pixels corresponds to a given column, wherein the multiplerows of pixels comprise at least two sets of two or more rows of pixels,wherein the array of photosensors is configured to expose each set oftwo or more rows of pixels for an exposure period, and wherein eachpixel in each set of two or more rows of pixels is simultaneouslyexposed for the exposure period; a plurality of analog-to-digital (A/D)converters coupled to the array of photosensors for generating digitalimage data from the captured image data; and a wide bus logic coupled tothe plurality of A/D converters for sequentially transferring portionsof the digital image data corresponding to image data captured by eachrow of pixels to a processor for processing the digital image data. 2.The barcode reader of claim 1, wherein each pixel of the grid of pixelscorresponds to a photosensitive region defined by a photodiodeconfigured to accumulate charge over the exposure period.
 3. The barcodereader of claim 1, where a number of A/D converters is equal to orexceeds twice a number of pixels in each row of pixels from the multiplerows of pixels.
 4. The barcode reader of claim 1, wherein the pluralityof A/D converters comprises: a first A/D converter coupled to each pixelfrom a first column of pixels from the multiple columns of pixels; and asecond A/D converter coupled to each pixel from a second column ofpixels from the multiple columns of pixels.
 5. The barcode reader ofclaim 1, wherein a duration of the exposure period is based on a numberof the plurality of A/D converters relative to a number of pixels ineach row of pixels from the multiple rows of pixels.
 6. The barcodereader of claim 1, wherein a number of the plurality of A/D convertersis equal to a multiple of a number of pixels in each row of pixels fromthe multiple rows of pixels.
 7. The barcode reader of claim 6, wherein aduration of the exposure period is based on the multiple of the numberof pixels in each row of pixels from the multiple rows of pixels.
 8. Thebarcode reader of claim 1, wherein the wide bus logic comprises aplurality of first-in-first-out (FIFO) buffers for buffering one or moredigital values of the digital image data prior to transferring theportions of the digital image data to the processor for processing thedigital image data.
 9. The barcode reader of claim 8, wherein theplurality of FIFO buffers comprises a FIFO buffer for each A/D converterfrom the plurality of A/D converters.
 10. The barcode reader of claim 1,further comprising a decoder configured to selectively determine aportion of the digital image data to be stored on a memory of thebarcode reader.
 11. A barcode reader, comprising: an array ofphotosensors organized in a grid of pixels including photosensitiveregions, the grid of pixels defined by multiple rows of pixels andmultiple columns of pixels, each row of pixels including a firstplurality of pixels, wherein each pixel of the first plurality of pixelscorresponds to a given column, wherein the multiple rows of pixelscomprise at least two sets of two or more rows of pixels, wherein thearray of photosensors is configured to sequentially expose each set oftwo or more rows of pixels, and wherein exposing a set of two or morerows of pixels comprises simultaneously exposing each pixel in the setof two or more rows of pixels; an optics system comprising one or morelenses configured to focus an image of a barcode onto the array ofphotosensors; a plurality of analog-to-digital (A/D) converters coupledto the array of photosensors for generating digital image data based ondata received from the array of photosensors; a wide bus logic coupledto the plurality of A/D converters for sequentially transferringportions of the digital image data corresponding to image data capturedby each row of pixels to a processor for processing the digital imagedata; and a decoder stored in memory, the decoder being executable todecode the barcode.
 12. The barcode reader of claim 11, wherein eachpixel of the grid of pixels corresponds to a photosensitive regiondefined by a photodiode configured to accumulate charge over an exposureperiod for measuring an intensity of illumination incident to thephotodiode.
 13. The barcode reader of claim 12, wherein a duration ofthe exposure period is based on a number of A/D converters relative to anumber of pixels in each row of pixels from the multiple rows of pixels.14. The barcode reader of claim 11, wherein the plurality of A/Dconverters comprises ache number of A/D converters is-equal to orexceeding a number of pixels in each row of pixels from the multiplerows of pixels.
 15. The barcode reader of claim 11, wherein theplurality of A/D converters comprises: a first A/D converter coupled toeach pixel from a first column of pixels from the multiple columns ofpixels; and a second A/D converter coupled to each pixel from a secondcolumn of pixels from the multiple columns of pixels.
 16. The barcodereader of claim 11, wherein the wide bus logic comprises a plurality offirst-in-first-out (FIFO) buffers for buffering one or more digitalvalues of the digital image data prior to transferring portions of thedigital image data to the processor for processing the digital imagedata, and wherein the plurality of FIFO buffers comprises a FIFO bufferfor each A/D converter from the plurality of A/D converters.
 17. Amethod for reading a barcode, comprising: capturing image data includingan image of the barcode using an array of photosensors, wherein thearray of photosensors is organized in a grid of pixels defined bymultiple rows of pixels and multiple columns of pixels to captureportions of image data corresponding to image data captured by each rowof pixels from the grid of pixels, wherein the multiple rows of pixelsinclude a first set of two or more rows of pixels and a second set oftwo or more rows of pixels, and wherein capturing the image data usingthe array of photosensors comprises: simultaneously exposing, beginningat a first time, the first set of two or more rows of pixels, whereineach pixel in the first set of two or more rows of pixel issimultaneously exposed for an exposure period; and simultaneouslyexposing, beginning at a second time after the first time, the secondset of two or more rows of pixels, wherein each pixel in the second setof two or more rows of pixels is simultaneously exposed for the exposureperiod; converting the captured image data to digital image data using aplurality of analog-to-digital (A/D) converters coupled to the array ofphotosensors; and sequentially transferring portions of the digitalimage data corresponding to image data captured by each row of pixels toa processor for processing the digital image data.
 18. The method ofclaim 17, wherein a duration of the exposure period corresponds to anumber the plurality of A/D converters.
 19. The method of claim 17,wherein converting the captured image data to the digital image datacomprises: converting a first portion of image data using a first A/Dconverter coupled to a first column of pixels from the multiple columnsof pixels; and converting a second portion of image data using a secondA/D converter coupled to a second column of pixels from the multiplecolumns of pixels.
 20. The method of claim 17, further comprisingdecoding the barcode by decoding the digital image data.